Will We Run Out Of Phone Numbers? | Neil deGrasse Tyson Explains...
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- čas přidán 4. 05. 2024
- Will we ever run out of phone numbers? On this explainer, Neil deGrasse Tyson and comic co-host Chuck Nice explore how you got your phone number, social security numbers, and permutations. Could we run out in our lifetimes?
When did we invent area codes? Neil takes us back to the days of operators and before phone numbers had area codes. Will we need to reuse social security numbers? What about shipment numbers? What happens when you add letters to an identification number? All that and more on another StarTalk explainer!
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Science meets pop culture on StarTalk! Astrophysicist & Hayden Planetarium director Neil deGrasse Tyson, his comic co-hosts, guest celebrities & scientists discuss astronomy, physics, and everything else about life in the universe. Keep Looking Up!
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0:00 - Introduction
1:14 - Social Security Numbers
9:11 - Phone Numbers
13:34 - Tracking Numbers
15:52 - Closing Notes - Věda a technologie
What's your country code?
+91 😇 IND
+27
55
+254
+351 (Portugal), so some countries have 3 digits for it :) which gives us even more combinations
This video reminded me of the classic 52 factorial. For similar reasons to what Dr Tyson explained, every time you shuffle a deck of cards it is statistically likely a combination that has never been shuffled before since cards were invented. There are 8.0658e67 different possible permutations of ways to arrange a standard deck of 52 cards. For comparison a billion years is approx 3.155692608e16 seconds
Whoa 🤯
True!
Vsauce has an excellent video on 52 factorial. I think the title is "Math Magic".
I love that the explainer of the movie inception was an explainer in a explainer in an explainer. Lord Nice pointing out the “explainer in an explainer” triggered another explainer of that.
It's turtles all the way down.
Who else as a child always loved switching your phone from tone to pulse. It was almost like a rotary phone.
Jim Otto was 00 on the Raiders. He called it 'ought-o' as in the pronounciation of his last name. He said he was the only player with his last name on the front of his jersey.
Anyone else old enough to remember dialing 7 numbers into a rotary phone or am I the only one? (And we had to rent the phone from the phone company)
I do, though I was a kid. It was my parents phone line.
I remember back late 90s early 00s. All I had to dial was 351-0261. Lol
I remember
Rotary phone and a party line. We knew everything about everyone 💯💯🤣🤣🤣
It's not that long ago....I don't think....has it been?
I started listening to the podcast 2014-2015, this explainer finally broke my brain 🤣
For Chuck to be a comedian, i have to give it up to him for keeping up with one of the brightest minds on the planet . Neil even pushes Chuck to answer some of the equations himself and Chuck is (usually)correct ,but that's ok when you're dealing with such a calculating mind like Neil's. 😉👍🏽
They're not exactly talking rocket science here. :)
@@bigbassjonz , Lol !😅💦 True on this occasion.
If we ever do run out of SSNs and they do not recycle them, it would be much easier and more efficient for them to add a letter at the beginning. Instead of increasing the SSN capacity by a factor of 10, you increase it by a factor of 26. This would be enough to last centuries.
You're right, this is a smart idea.
So funny watching chuck answer Neil's question 🤣🤣🤣 just like school, the way neil ask the questions, its so teacher like
He actually is though. Like Neil is in academia. He’s definitely taught actual student sun a classroom.
Entertaining and informative as always. Thanks for delivering info with a smile.
Just finished watching COSMOS. I just can not stop being touched by it. Carl Sagan's and Yours. So inspirational. Thank you. I could hold my tears by force but that changes nothing. And you are such a great actor too haha. Keep looking up!
This was great-would love to see more explainers about numbers.
Go subscribe to Numberphile :-)
StarTalk always makes my day and week!
Some country codes are 3 digits. Also, the + can be replaced with 00. So all in all there's enough capacity for 1 quadrillion phone numbers to exist simultaneously.
The plus is the extension number. Right?
@@StaticBlaster No, the plus symbol is for international dialling.
On some phones, you can literally dial a plus. For example, my UK mobile can call +1 for America.
On a landline, I'd dial 001.
Thank you for teaching me. I am forever grateful. I have learned a considerable amount from you.
Yes! I had a rotary phone! This explainer is so fun! Thanks Neil! Thanks Chuck!
Thanks for such an interesting and thought provoking discussion!
Love the references man; keep 'em coming.
Glad to finally catch a video this early! 🔥
Same.
Fr
I didn’t even realize I had clicked on it within the first two minutes until 5 minutes until the video!
I always learn something watching these Explainer videos, even if I do know little bit. I know I'm about 10 years too late but Neil, I enjoyed your performance as Waddles from Gravity Falls!
Canada and the US share international country codes, +1. Mexico is +52. The Telecom Union assigned Canada and the United States the same code as they both operated through a shared numbering plan at the time, nanp. Canada and the US also had the broadest and most connected network to the world. This is why the code was '1' and not a higher or more than a single digit number.
+1 is the code for the entire NANPA region, not just 🇨🇦 and 🇺🇸.
01152 🇲🇽
@@lawrencedoliveiro9104 yes, this includes areas like the Caribbean.
@TNerd Makes sense. Might be more efficient to spin off the Caribbean first. Things may be even less efficient there.
Explainer inception!!!!! Chuck’s timing is impeccable
Sir regular viewer from 🇮🇳India Your
explanation are very easy and grasping than our schooling. You make science loving ❤️
That's amazing info 👌
That was interesting and enjoyable.
Great explainer.
As a possible other topic. Numbers with error detection or numbers with error correction in them.
Error detection is used in bank account numbers. To try and avoid people from making a transfer to a wrong account number by accidentaly mistyping or misreading a digit. With error detection (by adding extra numbers in a special way in the string) the system can quickly detect something went wrong in the account number.
Error correction also adds numbers in the string, but in such a way that it can detect and even correct the string to what it should've been. Doctor Tyson could enjoy this one with data transmissions from satelites. When cosmic interference changes a few numbers while sending the signal, the receiving computer on earth could restore it to the original signal if the data send was a string of numbers with error correction in it.
Would love to see if doctor Tyson can explain this one easily 😅
Star talk can't exist without Chuck and Neil im sorry
As a Canadian, I can confirm that the +1 in front of the 10 digit phone numbers is shared for all of North America; it's not an exclusive country code for the US.
Thank you guys for helping me discover my love for STEM😭😭
I remember well my grandparents phone in their Bronx apartment. The prefix wasn't expressed in numbers, rather, Kingsbridge 4-xxxx, where the first two letters of Kingsbridge and 4 made up the prefix. 212 was the area code for the whole state.
15:05
Undeniable objective proof that Neil is truly a mortal like the rest of us. To see him access a calculator has justified my current use of them at least to some extent. lol
So you thought he was an alien or something. You guys are strange
I love his videos. Great guy.
Can't get enough of these...
I was so mad as a youngster in the early 90s when Houston started requiring us to dial the area code. Like the modern day half-second delay in web page loading, I felt so inconvenienced.
I mean, come on! My friend cant wait that long to hear from me!!!
Problem related to combinations and permutations perhaps expressed as factorial, mathematically.
The guy Chuck referenced was Lifelock the company. They're still around
I love the explainer videos however, FYI Social Security does have some reserved numbers for the first three digits but the theory is good. Also up to the early 70’s I lived in a area where you only needed to dial the last 4 numbers to call your neighbors. Please keep the information coming.
Nice explainer! Never really thought about these ID/serial/service tag numbers in this manner. 🤓 Someone correct me ... the "social security" hack example brought up ... Wasn't that the guy CEO from Lifelock? 🤔 Rings a bell.
lol yes it was him :P
my favorite youtube channel!!
I've needed this
Another StarTalk, life is good.
i took a math course once where they covered combinatorics, graph theory, stuff like that. hard as heck.
Yeah, I did one of those
The DJ is always dope af ... @16:07
No only do I remember dialing 7 digits, I remember the changeover from manual switching to dial. Your old manual phone number can be from one to four digits plus a letter like J or W at the end to identify party lines.
In the very early days in some small towns there were 3 and 4 digit phone numbers. I do remember as a kid visiting my Aunt in a small town. She had a 4 digit number.
Blessings from somalia my best astrophysict tyson and my smart chuck .
Growing up in Kansas city Kansas in the 50's we had 6 digits for our phone number. I remember when it went to 7 digits.
I had an aunt and uncle who lived on a farm, they had a party line. Depending on how many times it rang was the way you knew if it was for you.
I have more phone trivia, but that's enough for now.
Good show, thanks
Bob
Some numbers never get used because for some things you don't want the ids to increment by one or it would be easy to figure out what is the next id (think of a robocall dialing every phone number), so they increment by a random amount.
Until about 25 years ago, phone area codes always had either a zero or one as the middle digit. They had to change that when we ran out of numbers. Some business phone systems were programmed to also require that sequence and they needed to be updated to accept digits other than one or zero.
this is false, we've had a 4 as the middle digit of our area code since i first learned it 32 years ago.
@@chrisquinn8150 really? In the USA? What was the area code?
@@chrisquinn8150 en.wikipedia.org/wiki/Original_North_American_area_codes
@@chrisquinn8150 “Therefore, numbering plan area codes, often called just area codes, were defined to have three digits, with the middle digit being 0 or 1. Area codes with the middle digit 0 were assigned to numbering plan areas that comprised an entire state or province, while jurisdictions with multiple numbering plan areas received area codes having 1 as the second digit.”
@@lemongavine It changed in 1995, when places ran out of numbers. Alabama got the code 334, Washington 360, and Arizona 520.
Now there's lots.
Tom Scott did a great video on the CZcams video IDs and how they will never run out of them. Same concept.
Entropy is tricky for some alphanumeric numbering - sometimes the easily garbled letters are removed, such as 'I' and 'O' (for '1' and '0' respectively.) E.g. POWs in the Hanoi Hilton during the Vietnam War used a 5x5 code using taps on the wall to communicate prisoners on the other side. The code for 'i' and 'j' were combined to simplify the code and evade detection from guards.
I have a youtube video open with ID of 5vtH1uBaoBY Has both a #1 and letter o in there. It also seems youtube uses upper and lower cases to add more digits 26*2+10 so 62 unique identifiers per digit.
This conversation got me thinking about the enigma machine code breaking of world war 2. Which is what the movie" imitation game" is about.
11:55 it's true that area codes are 3 digits long, but no area code starts with 0 or 1, so the first digit is from 2 to 9 and I think the 200, 300, 400, etc are not used. The same applies to the phone numbers, so no phone number starts with 0 or 1. so phone numbers first digit starts with 2 to 9 as well. And some are codes are used outside USA by countries within calling zone 1 like Canada, Dominican Republic, Jamaica, Bahamas, etc so you can't count all the 10 digits "Zone 1" phone numbers as part of the USA.
Also the area codes are predefined/assigned by states, so if a state have 3 different area codes, the total number of phone numbers that state can have will be the amount allowed by the 7 digits phone number (counting the first digit from 2-9) multiplied by 3.
also the +1 can't be counted as a new digit, because that's just the international prefix, the same to the 011 or +11 for calling to countries outside calling zone 1.
Yeah, you're talking about specifics but these vary between countries and states. Neil was talking general principals.
@@toby9999 yeah, but at the same time he is talking about something specific when he mention the area code. But we understand the idea.
Neil I'm from Brazil and I love your videos with Chuck. Your English is easy to understand because you speak cleary and I thank you for that.
Could you please make a video explaining about earth rotation? That rotation more than a thausand kilometers around itself. And how the moon and the ISS work with It?
I have seached a lot but could not find anything about this. Thank you!
You and Carl Sagan are the most fantastic people on Earth and I can't believe I'm here writing to you!
Hey! Maybe this video can be of help: czcams.com/video/p9MAtyWEjZY/video.html
@@StarTalk thank you
I am glad he specified that he was working with pure numbers when talking about social security numbers because there is geographical meaning behind I believe the first 3 numbers which indicates where you lived when you obtained your number. Similar to area codes.
Not any more.
Since 2011, it's completely random.
Chuck is not a scientist but clearly highly intelligent. He makes a great counterpoint to the esteemed Dr Tyson. In a way he represents the audience. The formula works.
UK phone numbers have changed many times.
For example, London used to be "01".
Then it was split into "071" for inner London, and "081" for outer.
Then they added a 1 to all landline phone numbers, so it became 0171 and 0181.
Then, all London numbers changed to 020.
Man, Chuck's quick jokes about airline cust service, green acres, etc. just on fire today 🔥
In the early 1980's, I worked in the field for a car manufacturer, calling on 20+ dealers in Pennsylvania, some located in large cities, some in decent-sized towns, and a couple in extremely rural locations. One agency I visited was in a town so small that it had its own phone company, and everybody in town had 3 digit phone numbers (!). If I wanted to talk to anybody not in that town, it was simple: pick up the handset, tap the button that hangs up the phone, and wait a moment... the town operator would get on the line, greet me by name(!), and say: " Do you need to be connected to Gardena, California?" ( our headquarters....).
I would then hang up, and when the phone rang, I would answer and be told by the operator " Sir, I have Gardena on the line..."
She was using the type of switchboard you see in old movies...
Lots of wires plugged into a board....
Great episode, guys.
Also, I haven't flown enough to know the answer to this: do difference airlines share the codes collectively, or does each individual airline have its own separate "file"? If so, multiply your final result by the number of airlines...should give you a pretty big number...
I think he's talking about the fare basis code. That's not a unique code.
Lots of people going on the same flight will have the same code.
Each number/letter has a meaning. It shows the type of ticket.
For example, FYAHJNFC, means...
F - booking class (first)
YA - Advance purchase requirement (60 days)
H - day of the week (Saturday)
J - Time travel restriction (unknown)
NFC - nonrefundable first class ticket
However, each airline does it differently. That one is American.
There is also a passenger number, called a PNR. That's six numbers/letters, and is unique only for each flight. It's just to identify the person - in case their happens to be two people with the exact same name.
There's also the flight number, which isn't unique at all. It's two letters (for the airline), and up to 4 numbers representing the route. It doesn't need to be unique, because it's only used for booking.
Aircraft themselves have a registration number, which is unique. By international agreement, they all have to be registered with the CAA in their country. All American ones start with N, all UK ones start with G (for example).
i love this channel!
This was great
the title of this video (and content) reminds me of the book "foucalts pendulum" by umberto eco
How about "will we or have we" run out of combinations of notes to make original songs ? Saw that question asked to some genius once...like a genius, she skirted the answer brilliantly.
This episode is full od deep cuts in trivia
Haven't even started watching the video yet and I can say yes, we can run out of numbers. I only say that because my region ran out of phone numbers so they added another area code for the same region. Now, on to watch the video.
Check out E.164 - the maximum number of country codes is 3 digits, and the maximum number of subscriber numbers is 12 digits. The NANP might one day be extended to add 2 digits.
I have to fact check Neal on the counting of digits in international phone numbers. Not all countries follow the same 7 digit or 10 digit phone number patterns as the US uses.
Little correction on the phone numbers. Not every country has 10 digit phone numbers. And some (smaller) countries have 3 digit country codes (but those probably have fewer digit numbers).
SSN, prior to the 21st century, were done sequentially in certain ways so it was shockingly easy to figure out someones SSN if you know the SSN of someone else born in the same hospital, even easier if you have someone born on the same day but even yrs apart can be figured out by usin available census data and birth records.
Statistics is both the easiest AND hardest, but definitely also the most fun maths out there.
FedEx needs that many just to cover the lost/stolen packages ...so far this year . Great video guys ! Love this 💩!
LOL.
Make a video about phracking (phone cracking)
North America uses 1 (country code) plus 3 (area code) plus 7 digits for the phone number. Other countries have a different setup. The country code is always such that when you enter it, you get exactly that country and no other. For example, the UK has the country code 44. This means that no other country code will start with two consecutive fours, and not only that, no "area code" (or analogue thereof) will start with a 4 if the country is also 4 (which currently doesn't exist, but provisions are made just in case). The area code and phone number can vary in length even within the same country, for example most phone numbers in the UK will be 9 or 10 digits long, with some special codes being shorter - anywhere from 3 to 7 digits long (think out the USA has 911 and 411 as special codes).
Better solution to SS#'s: Go hexadecimal. 10^10=10,000,000,000 but 16^9=68,719,476,736. Also I think it would be easier on computer systems to allow A-F as characters than it would be to add another digit.
if you're going thru the trouble of going hexadecimal A-F, 0-9, why not go full alphanumeric and include the remaining G-Z as well? is it something to do with the 8-bits and bytes?
but yes, if you include all the births and deaths since FDR's time, and all the immigrants and their descendants, pretty sure we'd be hitting that Billion mark quite soon, assuming we haven't already
I would think using letters for SSN's would be just as complicated as adding another digit. I know many companies have software which only allow numeric digits in the SSN fields for data entry. Tons of software programs all across the country would probably have to be updated either way.
Chuck was super hilarious on this one😂😂
(Possible characters per slot)^(number of slots). This works only if it the same for each slot.
So for colors on a electronic device there are 4 slots with 256 Possible so there are 256^4 that makes 4,294,967,296 colors
Just a heads up the +1 county code is for Canada as well :) really it’s only used when calling any country other than USA and Canada :)
Overseas has 3 digits lol.
Anyways love your vids guys!! Keep it up :)
Thanks for the heads up!
Chuck is so funny! He should be a stand up comedian.
Original phone numbering system established by Ma Bell circa 1940's ?1930's when dial phones became common : initial digit 0=operator assisted call, initial digit 1=direct dial, area codes initial digit not 1 or 0, second digit 1 if more than one area code in a state, second digit 0 if only one area code in state, other digits low numbers in area codes with large volume of calls - 212 for NYC, 312 for chicago because dialing with old round dials takes longer for higher digits. Exchange numbers could not have the second digit be either 1 or 0, that way the system could tell if the three digits were an area code or local exchange. Last 4 digits could be anything. Some sequences were set aside for special uses so reducing the total available, i.e. 555 exchange number used for bogus numbers shown in movies or TV.
This began to break down with the proliferation of multiple phone lines for fax machines, teen lines in homes, etc. ant totally crashed when cell phones began to be common.
The reason I and probably you still get calls from the previous user of your phone number is that the number of digits (7) for each phone is kept deliberately low to enable people to remember it. The number of phones is relatively large compared to the possible different numbers so numbers must be reused when somebody closes an account. Perhaps with smart phones keeping track of most people's contacts the number of digits could be increased.
Back in the 1970's when I was in the military they had an upgrade to the National Stock Number, the number used for inventory of everything they used, from nuts and bolts to floor wax to paper clips to bullets - if you needed it from Supply it had a number. They apparently figured they were sometime soon going to run out of numbers so they added four digits in the middle. Old numbers continued to be used with -0000- in the middle, new numbers would presumably have other numbers later.
Your credit card probably has sixteen or more digits in your card number which would give possible combinations many millions more than the number of valid accounts. If you make up a number to buy something over the phone or internet, its a million-to-one chance that the number you invented is bogus. The field of possible account numbers is very lightly populated, compared to the seven digit field of phone numbers.
Kind of like ipv4, it was thought the address would never run out. Now were in ipv6 which is thought to never run out of combinations. Now some computer scientists are thinking these address may exhaust. Very Intersting.
Happy to see Dr. Tyson is one of the people who know to rotate the iPhone calculator to get a scientific calculator ;-)
My Dad actually worked for one of the phone companies in a management level, and he suggested in the 80's when beepers were popular, they needed to add another number before its too late, they all told him thats crazy. Neil is your math correct? with adding the country codes? because those are set to only those numbers for the country, so then they can reset the rest of numbers just for that country's use?
Your dad was right. 4 digit area codes might happen in our lifetimes. That would definitely solve that problem.
Also, you can't use the number of digits in a country code (3 digits here in Ireland) in the calculations for the maximum number of permutations since , within a country, that number never changes, so really you can even ignore it altogether.
@@christophelombardi7810 A layer beyond that country codes have consistently gained digits. I'm 75% of certain ours here in USA is still 1.
On a side note, a lot of alphanumeric codes will omit letters that resemble letters (I,O,Z…)
I have a youtube video open with ID of 5vtH1uBaoBY Has both a #1 and letter o in there. It also seems youtube uses upper and lower cases to add more digits 26*2+10 so 62 unique identifiers per digit.
The dash and the plus are characters also. Do they come into play as well? You could change them and blow the whole thing into oblivion?
I feel you chuck, Numbers confuses me as well
When are you going to do an explained on the black hole sounds, that will be interesting?!
the 1st 3# of a ssn indicate the the part of the US where the card was issued. these days the card is issued at birth but back in my day ppl applied for their card when they got their 1st job so it may not be where they were born. wont that impact the # of available #?
Used to do customer service for FedEx and always had to explain to people that if their tracking number contained letters it was for UPS not FedEx. FedEx is numbers only.
then if you use capital n lower case.. woah!
ps. you guys should have sung the Green Acres song
All of Kentucky was 606 area code. In early 2000's Lexington had to change to 859. Crazy
I'm a big fan from Jeddah City, Saudi Arabia. I've been watchimg and reading for Mr. Tyson since the Cosmos show.
Would love to hear your thoughts about Saudi's new futuristic city (NEOM) where everything is going to rely on AI and there will be zero carbon emmissions and how this city could help science and humanity overall.
That might be net zero, offsetting emissions with beneficial actions like planting trees. Zero carbon emissions isn't physically possible. One person farts and it's over.
Net zero is still a massive goal. I wish them the best of luck, and perhaps they can be an example for the near future.
As for AI running everything, that's its own saga.
It would be so nice to visit a warehouse filled with used previous phones 📞 📲 personally I think it would be interesting.
Where there are both letters and numbers being used, you probably won't find an "I" interchanged with 1 or an "O" interchanged with 0. So you are likely to have 34 alpha=numeric, not 36.
Wrong. I have a youtube video open with ID of 5vtH1uBaoBY Has both a #1 and letter o in there. It also seems youtube uses upper and lower cases to add more digits 26*2+10 so 62 unique identifiers per digit.
@@MrT------5743 So, can you tell the difference between l, 1, and I? One is lower case L, the 2nd is a one, and the 3rd is an upper case I. If I had to read off the digits verbally, I wouldn't know which is which. That is why you shouldn't interchange at least some of these characters.
Can you do an explainer about the lottery? Be it Pick 3, Pick 4, Powerball, Megamillions, etc
They're all terrible.
The chances of winning the jackpot in either Megamillions or Powerball are roughly 300 million to 1.
You're about 300 times more likely to get hit by lightning this year.
The chances of winning anything from Powerball is roughly 1 in 25, but 90% of those wins will only be $4.
If you buy $1,000 of Megamillions tickets, the average return is $64.
Also reminds me of computer grid lock .
The time decades of year. Was a concern.
🧐 I recall that. 1999 to 2000 . Not aiming for the grade only a thought as a comment.
I Remember LIN - 1234 (Lin = Lincoln Prefex) Why Not Go Back to This (Detroit Area) Previous to 313 Area Code...
Dial phones were awesome. If your finger didn't rotate the dial properly or correctly you would reach a wrong number. At work in the 70s I frequently received calls for a local bank with a similar number. I asked if they were using a dial phone...yep. I finally started answering the phone as " Royal Bank may I help you ? " I pulled a few pranks. 😁
Um all phones are dial phones. Now if you are talking rotary dial phones vs touch tone that is different.
In upper eastern NY they started running out of phone numbers for the 518 area code so they made a new area code of 838. So yes in some areas they are actually running out of phone numbers somehow.
Big companies, mostly. Whether it's land lines or cellphones, some individuals will have up to four phones. Some people even have multiple personal numbers. Throw millions of people into one area, average it out to maybe 1.5 phones per adult, grow the population via birth and migration...start running out of numbers. This happens in every big city.
The Star Talk episode from May 30, 2023 also explains a lot of this.
Also keep in mind that people with cell numbers can move and keep their number, so it remains claimed even though that person isn't in the area anymore, and has been replaced by a new person who may need another number. That won't be a majority by any means, but should be a notable percentage.
Fun Fact. The primary identifier of your cell phone isn't actually your phone number. Each device is identified in the system with a HEXADECIMAL ID number that is cross referenced to your common phone number to make it compatible with landlines and other places. Hexadecimal numbers multiply each numerical placeholder by 16 instead of 10. This is very common with computer systems. In fact, every single wired and wireless network adapter has a unique Hex ID assigned when it is manufactured. That's A LOT.
Shut up.
I think you're talking about MAC address, which is a different thing.
Mobile phones are identified by subscriber ID, on the SIM, which is a 14 or 15-digit decimal number. The first three digits are the country, and the next 2 or 3 are the network.
Mobile phones also usually have a unique number, built-in, called an IMEI. That's more like a serial number. It can be used to block stolen phones. It's got nothing to do with your phone number. If you put your SIM in a different phone, then that'll receive your calls.
A MAC address is used for network interfaces, such as inside a computer. It's usually written as 16 hexadecimal digits. Smart phones have a MAC address for their wi-fi.
@@ann_onn I worked with Motorola trunked radio networks and not cellular (nearly the same). We used hexadecimal for the subscriber I.D.'s. I assumed cellular was the same since Motorola invented it.