Ask A Scientist Mathematics Archive

Question:  What is the largest prime number that has been discovered?
Tim
 
Answer 1:
The largest known prime is very large, running to the hundreds if not
thousands of digits. New largest primes get discovered every few years.
I believe there was a good review article in _Scientific American_ a few
years ago. Check their index. Also, I think this question may have been
asked before. Did you check the math archive?
 hawley

Answer 2:  If you have access to a Web browser, check out URL
http://www.utm.edu/research/primes/largest.html  This page is maintained
by Chris Caldwell of the Department of Mathematics, University of
Tennessee - Martin. According to this page, the largest known prime is
2^859433-1. - 1 , which has 258,716 (yikes!) digits. Its primality was
announced on Jan. 4, 1994 by David Slowinski, who with Paul Gage proved
(using a Cray C90 supercomputer) that it was prime.
 rcwinther

Answer 3:
Hmmm, just looked at my answer and noted I'd managed to mistype the
prime number. I meant to type 2^859433 - 1 . The "^", by the way, means
"to the power of", so for example 2^3 means 2*2*2.