11111...11111 (217-digits)

This number is a prime.

                                                                     1111111
1112222222 2112333333 3211234444 4432112349 9999432112 3496666943 2112349677
7694321123 4967887694 3211234967 8587694321 1234967887 6943211234 9677769432
1123496666 9432112349 9999432112 3444444321 1233333332 1122222222 1111111111

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

        1 1 1 1 1 1 1 1 1
       1 2 2 2 2 2 2 2 2 1
      1 2 3 3 3 3 3 3 3 2 1
     1 2 3 4 4 4 4 4 4 3 2 1
    1 2 3 4 9 9 9 9 9 4 3 2 1
   1 2 3 4 9 6 6 6 6 9 4 3 2 1
  1 2 3 4 9 6 7 7 7 6 9 4 3 2 1
 1 2 3 4 9 6 7 8 8 7 6 9 4 3 2 1
1 2 3 4 9 6 7 8 5 8 7 6 9 4 3 2 1
 1 2 3 4 9 6 7 8 8 7 6 9 4 3 2 1
  1 2 3 4 9 6 7 7 7 6 9 4 3 2 1
   1 2 3 4 9 6 6 6 6 9 4 3 2 1
    1 2 3 4 9 9 9 9 9 4 3 2 1
     1 2 3 4 4 4 4 4 4 3 2 1
      1 2 3 3 3 3 3 3 3 2 1
       1 2 2 2 2 2 2 2 2 1
        1 1 1 1 1 1 1 1 1

The smallest hexagonal-congruent prime containing all of the non-zero digits. [Hartley]