The Largest Known Prime Number

The largest known prime number was discovered in 2016 by a computer laboratory of the University of Central Missouri .

257,885,161 – 1

is one of the Mersenne primes that can be written in form 2n – 1, where n is an integer.  They are named after 17-century French mathematician Marin Mersenne.


The number written in the decimal form contains 17 million digits.