The 22 million digit number and the amazing maths behind primes

PhysOrg ^ | 1/21/16 | Steve Humble

[politicianslie]

And these geniuses still don’t know how many shots were fired when President Kennedy was killed

[Rider on the Rain]

Not only that, but what red Bernie would do.

[IronJack]

I have a minor in math and I have never understood the fascination mathematicians have with primes. Okay, they’re only divisible by themselves and one. So what???

[Travis T. OJustice]

Man, you needed a fun math teacher in 4th grade like Mr. Mellon.

We had fun with this one day I obviously haven’t forgotten in over 4 decades.

https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes

[Travis T. OJustice]

Lol yes... No fault of the poster but as Cruz would say this article is to primes what Carter was to the Presidency.

The Cruz camp would also say prime numbers have withdrawn from consideration and slept with little boys or somesuch.

[Travis T. OJustice]

Chuckle/snort.

[NorthMountain]

[zeugma]

I've run a GIMPS client for a while. The numbers are so huge now though, that it takes weeks if not months to test a single number. Personally, I think it's astounding that they can factor a number like 2^74207281-1. That number is so large that it is pretty much imaginary. There is nothing in the universe that there is that many of.

I wish my drivers license or SSN were prime. Sadly, they are both divisable by 2. Yup.I'm a nerd.

[golux]

Maybe “conservatives” will eat each other alive the way they’ve done the last few times around and we can have Hillary for President!

[zeugma]

Holy Cow Batman!

[LibWhacker]

The fascination may have began with the frustrating fact that no one could find a formula that would predict the n^th prime given knowledge of some or all of the (n-1)st primes preceding it. Seems simple enough, but even to this day nobody has been able to do it. See my comments here and here for other reasons, which is by no means an exhaustive list. You could easily spend your whole life studying prime numbers.

[2 Kool 2 Be 4-Gotten]

Awesome - I’ll make this my number my next password at work.

[LibWhacker]

Not good enough. Your password must include at least one special character, one lower case letter and one upper case letter. ;-)

[IronJack]

All you need to know is that it’s not divisible by 2, 3, 5, or 7. That shouldn’t be that hard.

[Slicksadick]

Never had I thought to check, but my SS# is prime. Are there many 9 digit prime #s?

[CodeToad]

22 million digits is still small by cryptography standards.

It isn’t the logic behind a prime that is the hard part. Advanced logic must be created to shortcut the processing needed to find the prime. These numbers cannot be calculated directly and must be processed in chunks. That processing takes a looong time. So, the advanced math is about finding the next prime using math instead of processing.

[LibWhacker]

Lol, 121 is not divisible by 2, 3, 5 or 7. But it’s not prime.

[LibWhacker]

About 45 million. (Prime Counting Function)

[LibWhacker]

Oops, I take that back. It’s about 405 million.

[IronJack]

Lol! Yeah, I missed that whole concept. 121 is the square of 11, which is a prime itself. I think my rule only applies to numbers less than 100.