## prime number search

A new prime number with nearly 25 million digits was discovered just in time for Christmas.

Prime number enthusiasts discover new largest prime with 22,338,618 digits.

*257,885,161-1*. This massive 17,425,170 digit number was discovered thanks to clever distributed computing software that uses idle computer time donated by volunteers.

**Julian Havil**looks at a little-known algorithm that sieves out all primes up to a given number, and which is astonishing in its simplicity.

**Abigail Kirk**investigates a method that does just that.

The Great Internet Mersenne Prime Search strikes again