Wednesday, March 30, 2005
On this day:

World's Largest Known Prime Number Discovered

The number, rendered in exponential shorthand, is (2^25,964,951) - 1. (That caret is supposed to indicate that the number following it is an exponent, so you'd say it "two to the 25,964,951 (pause) minus one.") The number is a Mersenne prime, which is a prime number taking the form of (2^p) -1, or "two to the p (pause) minus 1".

Someone tell Derb.