11111...11111 (91-digits)

This number is a prime.

                                                     1 1111111111 1111111111
1111111111 1111111111 1111511111 1111111111 1111111111 1111111111 1111111111

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

The largest Palindromic Wing prime less than a googol. [Gupta]