Mersenne prime

A Mersenne [prime] is a prime that is in the form of .

These are some of the largest primes known to man due to one main factor: There is an integer bit value set to that, so that the largest number with a certain amount of bits is a form of

For example: The amount of numbers on a 32 bit computer is . Then, divide by 2, as there are positive, and negative values. Then subtract one, as zero is one of them, so the largest number on a 32 bit computer is 2,147,483,647. (Not necessarily the largest number displayed, to achieve a higher number, a computer could use a base system other than 2.)

The largest prime is , and it is a Mersenne prime.