10011111122113

This number is a prime.

                                                             1001 1111122113

+ The only prime less than a googol formed by concatenating alternately the first n double-digit numbers and their reversals, i.e., 10, 01, 11, 11, 12, 21, 13. [Loungrides]

Printed from the PrimePages <primes.utm.edu> © G. L. Honaker and Chris K. Caldwell