47th Mersenne Prime Identified

June 30, 2009

On April 12, 2009, the 47th Mersenne prime—12,837,064 decimal digits long—was found. This prime, which is the second largest known prime number, is only 141,125 digits smaller than the Mersenne prime uncovered last August.

Mersenne primes have the form 2^p - 1, where p is a prime number. The newly found prime is 2^42,643,801 - 1.

Odd Magnar Strindmo, from Melhus, Norway, zeroed in on it after testing 1,400 other candidates since 1996. An IT professional whose computers have been working with the Great Internet Mersenne Prime Search (GIMPS), Strindmo did his calculations in 29 days on a 3.0 GHz Intel Core2 processor.

This is the 13th Mersenne prime found by GIMPS in its 13-year history. Since Mersenne primes are factors of even perfect numbers, the discovery means the world of mathematics has a new perfect number!

The prime candidate was verified June 12th, 2009, by Tony Reix of Bull SAS in Grenoble, France.

Source: Great Internet Mersenne Prime Search.