UCLA researchers find prime number worth $100,000

Published Sunday, September 28, 2008

LOS ANGELES (AP) - Mathematicians at the University of California, Los Angeles have discovered a 13 million-digit prime number, a long-sought milestone that makes them eligible for a $100,000 prize.

The group found the 46th known Mersenne prime last month on a network of 75 computers running Windows XP. The number was verified by a different computer system running a different algorithm.

It’s the eighth Mersenne prime discovered at UCLA.

Primes are numbers such as three, seven and 11 that are divisible by only two whole positive numbers: themselves and one.

Mersenne primes - named for their discoverer, 17th century French mathematician Marin Mersenne - are expressed as 2P-1, or two to the power of "P" minus one. P is itself a prime number. For the new prime, P is 43,112,609.

Thousands of people around the world have been participating in the Great Internet Mersenne Prime Search, or GIMPS, a cooperative system in which underused computing power is harnessed to find and verify Mersenne primes.

The $100,000 prize is being offered by the Electronic Frontier Foundation for finding the first Mersenne prime with more than 10 million digits. The prize could be awarded when the new prime is published, probably next year.