Two New Mersenne Primes Discovered

Two new Mersenne primes have been discovered. The smaller of the two was discovered on September 6th by Hans-Michael Elvenich in Langenfeld, Germany:
2^{37,156,667} - 1,

It’s an 11,185,272-digit number which is available for download here. The larger one was discovered first on August 23rd by Edson Smith, who installed the prime-checking software on computers at UCLA. At 12,978,189 digits, it is now the largest known prime:

2^{43,112,609} - 1.

The two numbers were discovered by using a distributed computing project on the Internet called Great Internet Mersenne Prime Search (GIMPS).

A Mersenne number is a positive integer that is one less than a power of two:

\displaystyle M_n=2^n-1.

Only 46 Mersenne numbers are known. Read more over at Wikipedia’s entry.