GIMPS Discovers 45th and 46th Mersenne Primes,

243,112,609-1 is now the Largest Known Prime.

Titanic Primes Raced to Win $100,000 Research Award

SAN DIEGO, California and ORLANDO, Florida, September 15, 2008 — Researchers have discovered the two largest known prime numbers, a whopping 12,978,189 and 11,185,272 digits long, as part of a 12 year old, world-wide volunteer computing project, the Great Internet Mersenne Prime Search ("GIMPS"). The primes can be written shorthand as 243,112,609-1 and 237,156,667-1. The larger number qualifies for a $100,000 research award, most of which GIMPS will donate to the University of California, Los Angeles (UCLA), and to charity.

In recognition of every GIMPS participant's contribution, credit for the qualifying prime goes to "Edson Smith, George Woltman, Scott Kurowski, et al", and the other to "Hans-Michael Elvenich, George Woltman, Scott Kurowski, et al".

A nearly decade-long competition for a $100,000 award from the Electronic Frontier Foundation ended closely when the larger prime surfaced on a UCLA computer managed by Edson Smith, just two weeks before the second prime was found by Hans-Michael Elvenich's computer, in Langenfeld near Cologne, Germany. Both are among the 100,000 computers in GIMPS PrimeNet, a "grass-roots supercomputer" as Science magazine describes it, which has been running continuously since 1996 and performs 29 trillion calculations per second. Had Elvenich's prime been discovered first, it would have qualified, instead.

"We're proud be to participants in GIMPS and grateful to the UCLA Mathematics Department for providing computational resources to the project," said Edson Smith, Computing Manager. Hans-Michael Elvenich, a German electrical engineer and prime number enthusiast, adds, "After four years of searching for a prime on GIMPS, finally a great success!"

"These exciting discoveries are literally at the Internet's 'electronic frontier'," says PrimeNet inventor, Scott Kurowski, a software technologist in San Diego, California. "Developing technologies and methods to apply the incredibly vast power of cooperative research computing is why the Electronic Frontier Foundation set up their grand challenge awards. It's serious research, but fun and educational, too."

GIMPS founder George Woltman in Orlando, Florida said, "In addition to congratulating and gratefully acknowledging the vast contributions of our hundreds of thousands of participants over the years, we're committed to giving $25,000 to charity, $50,000 to UCLA for its part in the discovery, and most of what's left to other GIMPS prime discoverers." He adds, "Our research project will soon offer the chance to achieve the next challenge, the $150,000 award for an immensely more difficult 100-million-digit prime. All you need to participate is our free software download, and a lot of patience!"

For more information, see www.mersenne.org.