37079...00001 (81-digits)

This number is a prime.

                                                                3 7079160476
9783808000 0000000000 0000000000 0000000000 0000000000 0000000000 0000000001

The largest known prime factor of a googolplex + 1 (i.e., 10¹⁰¹⁰⁰ + 1) as of 2008. [Beedassy]