11156...74137 (31-digits)

This number is a prime.

                                          1 1156415441 1759146232 6794074137

1115641544117591462326794074137 = 5^11+53^11+59^11+503^11+509^11. Note that 5, 53, 59, 503 and 509 are the first 5 primes starting with the prime digit 5. [Bajpai]