A participant in the Great Internet Mersenne Prime Search (GIMPS) has identified the largest prime number yet. When printed out, its digits would fill more than 450 pages of Science News.
Discovered by 20-year-old Michael Cameron of Owen Sound, Ontario, the new champion prime is 213,466,917 – 1, which runs to 4,053,946 decimal digits.
A prime is a whole number evenly divisible by only itself and 1. Cameron's number belongs to a special class of extremely rare primes named after 17th-century mathematician Marin Mersenne.
A Mersenne number can be expressed in the form 2p – 1, where the exponent p is a prime. Only a handful of these numbers are also themselves prime. The new record holder is just the 39th known Mersenne prime.
Cameron discovered the record-setting prime using software written by George Woltman, a retired computer programmer in Orlando, Fla. Woltman started the GIMPS project in