139717931

This number is a prime.

The only 9-digit palindromic prime in a 156-digit number found by L. E. Card: 3 1 3 7 1 3 1 3 7 3 1 9 1 9 7 9 3 1 1 9 1 9 1 7 3 3 7 1 9 3 9 7 1 7 3 7 3 9 9 1 1 1 9 1 3 7 3 3 9 9 9 3 1 9 7 7 7 1 9 3 3 3 7 7 1 7 1 1 7 9 1 7 3 3 3 9 3 9 1 1 9 7 1 1 7 3 7 3 1 1 9 9 9 1 1 1 1 7 9 9 1 7 3 9 1 3 3 7 9 1 1 7 1 9 3 7 3 7 7 3 1 3 3 9 1 9 3 7 1 7 9 3 1 1 9 9 1 7 3 7 3 1 3 9 7 1 7 9 3 1 9 3 3 7 9 9. [Bajpai]