100! = 93326215443944152681699238856266700490715968264381621468592963895217599993229915608941463976156518286253697920827223758251185210916864000000000000000000000000
Length: 158 digits

M31 (2^31 - 1) = 2147483647
M31 is prime.
M61 (2^61 - 1) = 2305843009213693951
M61 is prime.

(7^123) mod 100 = 43