This prime is not an ordinary prime, either. It is a Mersenne prime.

And, as everybody knows, a Mersenne prime can be written in the form 2

^{p}−1, meaning that it's a power of two, minus one. That's the binary number consisting of 1 followed by p zeros, with one subtracted.

That, in turn, means it's the binary number that consists of the bit 1 repeated p times.

Mersennes are denoted by M(p), where p is the power of 2 they're one less than, or just as

**Mn**, where n indicates the prime's position in the pecking order.

The lowest Mersenne prime is 3. All Mersennes are odd number.

The new prime discovered recently, 2

^{57,885,161} − 1, which is also the largest known prime, is only the 48th Mersenne prime so far discovered, giving it the name M48. It has 17,425,170 digits.

Since 1997, all newly-found Mersenne primes have been discovered by the “Great Internet Mersenne Prime Search” (GIMPS), a distributed computing project on the Internet.

As of November 2012, GIMPS has a sustained throughput of approximately 95 teraflops, theoretically earning the GIMPS virtual computer a place among the TOP500 most powerful known computer systems in the world.

But could this new prime really be M48? In other words, could there be another Mersenne prime lurking between this one and M47, which is a mere 2

^{43112609}−1?

In fact, according to GIMPS, only the first 41 Mersennes truly qualify to be called M1..M41. From M42 to M48, we're still unsure.

**Edited by TheLastLazyGun, 07 February 2013 - 03:21 PM.**