323232323

This number is a prime.

A smoothly undulating palindromic prime formed from digits 2 and 3, whose sum of digits is 23. [Silva]

     3 2 3   
     2 3 2 
     3 2 3   
     

The smallest X-prime. Not to be confused with the marketing agency "X-Prime" headquartered in Toulouse, France! [Loungrides]