33333...33333 (61-digits)

This number is a prime.

         3 3333333333 3322233332 5523333257 5233332552 3333222333 3333333333

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

    3 3 3 3 3
   3 3 3 3 3 3
  3 3 2 2 2 3 3
 3 3 2 5 5 2 3 3
3 3 2 5 7 5 2 3 3
 3 3 2 5 5 2 3 3
  3 3 2 2 2 3 3
   3 3 3 3 3 3
    3 3 3 3 3

The smallest centered hexagonal-congruent prime that contains all the prime digits. [Hartley]