Largest known prime number facts for kids
A prime number is a special kind of integer (a whole number). It's a number greater than 1 that can only be divided evenly by 1 and itself. For example, 7 is a prime number because you can only divide it by 1 and 7. But 6 is not prime because you can divide it by 1, 2, 3, and 6.
The largest known prime number is the biggest prime number that people have found so far. As of January 7, 2016, this amazing number is 274,207,281 − 1. Imagine how huge that is! If you tried to write it down, it would have 22,338,618 digits. That's more than 22 million digits!
Finding the Biggest Prime Numbers
People have been looking for the largest prime numbers for a very long time. It's like a treasure hunt for mathematicians! Finding these huge numbers often involves powerful computers.
Mn is a short way to write a special kind of prime number called a Mersenne prime. It means 2n − 1. These numbers are named after a French monk and mathematician, Marin Mersenne. Many of the largest known prime numbers are Mersenne primes.
This table shows some of the numbers that were once the largest known prime numbers. The first record we know of was from 1456. The number 524,287 was the largest known prime for 144 years!
| Prime number | Number of digits | Year found | Notes | |
|---|---|---|---|---|
| M13 | 8,191 | 4 | 1456 | We don't know who found this one. |
| M17 | 131,071 | 6 | 1460 | The finder is unknown. |
| M19 | 524,287 | 6 | 1588 | Found by Pietro Cataldi. |
| (232+1)/641 | 6,700,417 | 7 | 1732 | Found by Leonhard Euler, a famous mathematician. |
| M31 | 2,147,483,647 | 10 | 1772 | Also found by Leonhard Euler. |
| M127 | 170,141,183,460,469,231,731,687,303,715,884,105,727 | 39 | 1876 | Found by Édouard Lucas. This was a huge jump in size! |
| (2148+1)/17 | 20,988,936,657,440,586,486,151,264,256,610,222,593,863,921 | 44 | 1951 | Found by Ferrier. This was the largest record found without a computer. |
| 180×(M127)2+1 | 79 | 1951 | This was found using an early computer called EDSAC in Cambridge. | |
| M521 | 157 | 1952 | The first Mersenne prime found by a computer. | |
| M1279 | 386 | 1952 | Found in the same year, showing how computers sped things up. | |
| M19937 | 6,002 | 1971 | Found by Bryant Tuckerman. | |
| M86243 | 25,962 | 1982 | Found by David Slowinski. | |
| M216091 | 65,050 | 1985 | Found by David Slowinski. | |
| M756839 | 227,832 | 1992 | Found by the Great Internet Mersenne Prime Search (GIMPS) project. | |
| M2976221 | 895,932 | 1997 | The first prime number with over a million digits! Found by GIMPS. | |
| M6972593 | 2,098,960 | 1999 | Found by Nayan Hajratwala (GIMPS). | |
| M20996011 | 6,320,430 | 2003 | Found by Michael Shafer (GIMPS). | |
| M32582657 | 9,808,358 | 2006 | Found by Curtis Cooper and Steven Boone (GIMPS). | |
| M43112609 | 12,978,189 | 2008 | Found by Edson Smith (GIMPS). | |
| M57885161 | 17,425,170 | 2013 | Found by Curtis Cooper (GIMPS). | |
| M74207281 | 22,338,618 | 2016 | The current largest known prime number, found by Curtis Cooper (GIMPS). | |
Images for kids
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A special postmark from the UIUC Math Department. It was used after they proved that M11213 is a prime number.
See also
In Spanish: Mayor número primo conocido para niños
