# Volunteer discovers a new 17 million-digit prime number

#### Ars Technica » Scientific Method 2013-02-05

A new largest prime number has been discovered, mersenne.org reported Tuesday. 2^{57,885,161}-1, which is also the 48^{th} Mersenne prime, was discovered on the computer of Dr. Curtis Cooper, a professor at the University of Central Missouri.

A Mersenne prime is a prime number that can be written in the form M_{p} = 2^{n}-1, and they’re extremely rare finds. Of all the numbers between 0 and 25,964,951 there are 1,622,441 that are prime, but only 42 are Mersenne primes.

The 48^{th} Mersenne prime was discovered as part of the Great Internet Mersenne Prime Search (GIMPS), a project that has used volunteer computers to calculate and search for primes for 17 years. Dr. Cooper’s computer took 39 days of continuous calculation to verify the prime status of the number, which has over 17 million digits and was discovered January 25. GIMPS’ algorithm was developed in the early 1990s by Richard Crandall, an Apple Distinguished Scientist.