11111...11111 (81-digits)

This number is a prime.

                                                                1 1111111111
1111111111 1111111111 1111111116 1111111111 1111111111 1111111111 1111111111

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

1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1
1 1 1 1 6 1 1 1 1
1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1

The smallest near-repdigit square-congruent prime of order 9. [Hartley]