23

This number is a prime.

Just showing those entries submitted by 'Russo': (Click here to show all)

Smallest prime p such that 90*p+11, 90*p+13, 90*p+17, 90*p+19 are all primes. [Russo]

The smallest prime p that divides the number of digits of p!. [Russo]

(There is one curio for this number that has not yet been approved by an editor.)