# March 25, 1992

On March 25, 1992, British scientists announced that they had discovered the largest Mersenne prime number to date. A Mersenne prime number is a prime number that is one less than a power of two. For example, two squared is four, and one less is three, and three is a prime number, so three is a Mersenne prime number. Two cubed is eight and eight minus one is seven, and seven is prime, so seven is a Mersenne prime. The more you increase the power of two, the harder it becomes to find a Mersenne prime. Before 1992, the last time a Mersenne prime was discovered was in 1985, and the Mersenne prime number then was two to the power of 216,091, minus one. That number if written out had 65,050 digits in it. In 1992, the newly discovered Mersenne prime number, only the 32nd one ever discovered in history, was two to the power of 756,839, minus one. This number if written out was 227,832 digits long. If a person wrote three digits per second, it would take 75,944 seconds, or 1,265 minutes, or 21 hours to write this number by hand. The British scientist used computers to find this latest Mersenne prime. It’s not twisted, but it is very interesting to know. 