# Largest known prime number found

## The Great Internet Mersenne Prime Search, a cooperative computing project, helps find a prime that has nearly 13 million digits.

**Editor’s note**: This story was originally posted on Science
News online as a Math Trek column September 20.

Here’s a number to savor: 243,112,609-1.

Its size is mind-boggling. With nearly 13 million digits, it makes the number of atoms in the known universe seem negligible, a mere 80 digits.

And its form is tidy and lovely: 2n-1.

But its true beauty is far grander: It is a prime number. Indeed, it is the largest prime number ever found.

The Great Internet Mersenne Prime Search, or GIMPS, a computing project that uses volunteers’ computers to hunt for pri