Robert Brook/Getty It’s time for a new prime to shine. The largest known prime number is now 274,207,281 – 1, smashing the previous record by nearly 5 million digits.

This mathematical monster was discovered by Curtis Cooper at the University of Central Missouri in Warrensburg as part of the Great Internet Mersenne Prime Search (GIMPS), a collaborative effort to find new primes by pooling computing power online. It has 22,338,618 digits in total.

The GIMPS software automatically crunches through numbers, testing whether they are prime – that is, only divisible by themselves and one. Cooper’s computer actually found the prime on 17 September 2015, but a bug meant the software failed to send an email alert reporting the discovery, meaning it went unnoticed until some routine maintenance a few months later.


Cooper also discovered the previous record holder in February 2013, which was 257,885,161 – 1, a number with more than 17 million digits, along with two other older records. He has received a $3000 prize from GIMPS for each discovery.

All of the GIMPS primes are Mersenne primes, which take the special form 2p – 1, where p is also a prime number. Only 49 are known, and the GIMPS project has discovered the last 15.

The prime numbers are infinite, and there is little practical use in discovering one, but the search is a good way to put computing hardware through its paces. Unrelated to the discovery of the new prime, GIMPS recently helped discover a bug in Intel’s new Skylake processors, which were crashing under the heavy workload.