31111...11117 (219-digits)

This number is a prime.

                                                                   311111111
1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111
1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111
1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111117

+ The first prime after 317 in the sequence 37, 317, 3117, 31117 etc.

Printed from the PrimePages <t5k.org> © G. L. Honaker and Chris K. Caldwell