Gimps project finds longest prime number to date

An American volunteer from the Gimps project has found the fiftieth known Mersenne prime. The prime number 277,232,917-1 consists of 23,249,425 digits, making it almost a million digits larger than the previous record holder.

The fiftieth known Mersenne prime has been found by 51-year-old American Jonathan Pace, who has been working on the Gimps project for fourteen years and who earns three thousand dollars from his find. The prime number designated M77232917 is obtained by raising 2 to the 77,232,917 power and then subtracting 1.

This is a Mersenne prime: a prime that is exactly one less than the power of two, or 2n – 1. These kinds of primes are notoriously difficult to find. They are named after the French monk Marin Mersenne, who studied them 350 years ago. The Gimps project was started in 1996 and has found the last sixteen Mersenne numbers. The previous one dates from January 2016, when a prime number of 22,338,618 digits was found.

The proof was found after six days of continuous calculations with the Prime95 tool on a PC with an Intel Core i5-6600. Then it was confirmed with the programs gpuOwL on an AMD RX Vega 64 in 34 hours, CUDALucas on an Nvidia Titan Black GPU in 73 hours, Mlucas on a Xeon server in 82 hours and on an Amazon AWS instance in 65 hours.