A New Really, Really Big Prime Was Found! Woo Hoo!

On January 25, the largest prime to be discovered to date was “found”.  I use the word found in quotes, because the special number found was determined as part of the Great Internet Mersenne Prime Search (GIMPS).  Mersenne primes are prime numbers of the form:

where P is itself a prime number.  The  numbers 3, 7 and 31 are Mersenne Primes, corresponding to P’s of 2, 3 and 5.  In the GIMPS program, anyone with a computer can help search for new Mersenne primes by installing a program on their computer, which runs quietly in the background.  The recently found prime is the 48th Mersenne Prime to be found, and has over 17 million digits.  It’s not often that math is news, so this is a great opportunity to use something “ripped from the headlines”.

This is big, exciting news in the math community!  And the finding was heralded by an article on, which included the following passage:

Prime numbers, which are divisible only by themselves and one, have little mathematical importance. Yet the oddities have long fascinated amateur and professional mathematicians.

First, thanks to Fox News for pouring cold water on this big discovery.  Prime numbers are hardly oddities, and play a big role in much of the math we all do.  And, prime numbers, while often taught as a trivial notion, play a vital role in our national, world, and personal security.  In fact, the whole idea of RSA cryptography, that which keeps our data secure in thsi data-driven world, relies on prime numbers.  A quick search turned up some useful site which explain the role of the prime number.  Enjoy them, share the news with your students, and celebrate the discovery!

Prime Numbers and Cryptography – Clay Math Institute

RSA explained using paper and pencil

RSA numbers – from Wolfram Mathworld

RSA cryptosystem – prime glossary


By Bob Lochel

HS Math Teacher. Hatboro-Horsham School District, Horsham, PA.

One reply on “A New Really, Really Big Prime Was Found! Woo Hoo!”

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