91919...11111 (121-digits)

This number is a prime.

                    9 1919191911 1911191119 1119111911 1119111119 1111191111
1911111119 1111111911 1111191111 1111111111 1111111111 1111111111 1111111111

+ A cryptic prime number known as "SS-121".

Printed from the PrimePages <t5k.org> © G. L. Honaker and Reginald McLean