US researchers find world's largest prime number
KANSAS CITY, Missouri (AP) - University of Central Missouri mathematicians have found the largest prime number ever identified, but good luck remembering it.
The researchers identified the 17 million-digit number last month as the 48th known Mersenne prime. A different computer system running on different hardware confirmed that it is a prime number. Primes are whole numbers such as 3, 7 and 11 that can only be divided without a remainder by themselves and 1.
This is the third Mersenne prime identified at the university, about 80km east of Kansas City.
Mersenne primes are named after their discoverer, 17th century French mathematician Marin Mersenne. They're expressed as 2P-1, or two to the power of "P" minus one. P is itself a prime number. For the new prime, P is 57,885,161.