(Phys.org)—A team at the University of Central Missouri, headed by Curtis Cooper has announced, via press release from the Mersenne organization, that they have found the largest prime number ever—it is 2^{74,207,281} – 1, it has over 22 million digits. The new record has broken the old record by approximately 5 million digits.

Cooper and his team are part of the Great Internet Mersenne Prime Search (GIMPS) collaboration, which as its name suggests, is an effort by a lot of volunteers to find ever larger prime numbers—or, more specifically, a particular class of prime numbers that are called Mersenne, where it is one less than a power of two. Not surprisingly, Cooper and his team also held the old record, they have actually broken the record four times. He has told the press that he was notified by an email sent by the software running on a PC that the prime number had been found. The find came after a month of number crunching on a single Intel based PC. Interestingly, the PC tried to notify Cooper and his team about the find back in September of last year, but a glitch prevented it from being sent. It was only during a maintenance cycle that the message reporting the number prime number found, was sent. The official discovery date is January 7^{th}.

The search for new and bigger prime numbers is conducted using software developed by the GIMPS team, called prime95—it grinds away, day after day, until a new prime number is found. And while the numbers that it finds are of interest, they no longer serve much if any practical use, the software has been used for other purposes though—it has found flaws in Intel CPUs, for example.

The new prime number has been named M74207281—in the press release, the team says that it was "calculated by multiplying together 74,207,281 twos then subtracting one." It has already been tested and confirmed by three different independent teams running software on different machines. The find makes Cooper eligible for a $3000 award. The GIMPS group also made known their goal of winning a hundred and fifty thousand dollar award by finding a prime number with 100 million digits.

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University professor discovers largest prime number to date

## nilbud

## someone11235813

## viko_mx

## antialias_physorg

Wow, didya figure that out all by yourself, Einstein? That's 5th grade school stuff.

## Nik_2213

Simply 'Due Care'...

## ogg_ogg

## antialias_physorg

That 'digit by digit' representation is less than one of your porn movies and represents a monetary amount of disc space that is less than a single cent. To be exact it's a string of 74207280 bits (about 9 MB).

Make one up. Or just take the largest file that exists and declare it an integer representation. (Take the same file and declare it a fraction and you have your record of the smallest integer ever recorded). There's no real point for either.

There IS however a point for checking Mersenne primes (seeing if the prediction holds true and also optimizing factorisation algorithms which have a lot of applications in cryptography)

## EnsignFlandry

There is Graham's Number, which is not THE largest. Still, it would take more than the diameter of the visible universe to write down all of its digits. Then add 1. Or add another Graham's Number. Or raise Graham's number to the Graham's Number power. Or....

## antialias_physorg

http://www.xkcd.com/207/

There's an entire thread on the xkcd forums titled "My Number Is Bigger!".

(or just use "corporal")