 | ||
As of January 2017, the largest known prime number is 274,207,281 − 1, a number with 22,338,618 digits. It was found in 2016 by the Great Internet Mersenne Prime Search (GIMPS).
Contents
Euclid proved that there is no largest prime number, and many mathematicians and hobbyists continue to search for large prime numbers.
Many of the largest known primes are Mersenne primes. As of January 2017, the six largest known primes are Mersenne primes, while the seventh is the largest known non-Mersenne prime. The last 16 record primes were Mersenne primes.
The fast Fourier transform implementation of the Lucas–Lehmer primality test for Mersenne numbers is fast compared to other known primality tests for other kinds of numbers.
The current record
The record is currently held by 274,207,281 − 1 with 22,338,618 digits, found by GIMPS in 2015 and discovered by humans the following year. Its value is:
300376418084606182052986098359166050056875863030301484843941693345547723219067994296893655300772688320448214882399426727
... (22,338,378 digits omitted) ...
717774014762912462113646879425801445107393100212927181629335931494239018213879217671164956287190498687010073391086436351
The first and last 120 digits are shown above.
Prizes
The Great Internet Mersenne Prime Search (GIMPS) currently offers a US $3000 research discovery award for participants who download and run their free software and whose computer discovers a new Mersenne prime having fewer than 100 million digits.
There are several prizes offered by the Electronic Frontier Foundation for record primes. GIMPS is also coordinating its long-range search efforts for primes of 100 million digits and larger and will split the Electronic Frontier Foundation's US $150,000 prize with a winning participant.
The record passed one million digits in 1999, earning a $50,000 prize. In 2008 the record passed ten million digits, earning a $100,000 prize and a Cooperative Computing Award from the Electronic Frontier Foundation. Time called it the 29th top invention of 2008. Additional prizes are being offered for the first prime number found with at least one hundred million digits and the first with at least one billion digits. Both the $50,000 and the $100,000 prizes were won by participation in GIMPS.
History
The following table lists the progression of the largest known prime number in ascending order. Here Mn= 2n − 1 is the Mersenne number with exponent n. The longest record-holder known was M19 = 524,287, which was the largest known prime for 144 years. Almost no records are known before 1456.
GIMPS found the thirteen latest records (all of them Mersenne primes) on ordinary computers operated by participants around the world.