19

This number is a prime.

Single Curio View: (Seek other curios for this number)

The index p of the largest known Mersenne prime M_p = 2^p - 1 having an associated perfect number M_p*2^{p - 1} that is short of a prime by 1. [Beedassy]

Submitted: 2009-05-02 05:10:50; Last Modified: 2009-05-02 17:46:00.