Mersenne prime
Cooper and Boone became the first GIMPS contributors to find two primes when they also found the 44th known Mersenne prime, 232,582,657 − 1 (or M32,582,657), which has 9,808,358 digits . This prime was discovered on September 4, 2006 using a PC cluster of over 850 machines. This is the tenth Mersenne prime for GIMPS.