77232917

This number is a prime.

The exponent in the fiftieth known Mersenne prime is a concatenation of two four-digit primes, 7723 and 2917. These primes have the same prime sum of digits, (19). Note that this is the 2nd case in which the exponent in a Mersenne prime is a concatenation of two primes with the same length. The first such case is the exponent 859433 in the 33rd Mersenne prime. [Loungrides]

The fiftieth Mersenne prime exponent is the first such exponent that starts and ends with the same prime digit. [Loungrides]

The sequence of digits '77232917' does not appear in the Mersenne prime 2^77232917 - 1. [Harrison]

The Mersenne prime exponent '77232917' contains a record-breaking eleven prime substrings when read left-to-right, i.e., 2, 3, 7, 17, 23, 29, 2917, 7723, 23291, 32917, 7232917. [Harrison]

The largest known Mersenne prime exponent to comprise six instances of a prime digit, i.e. 7, 7, 2, 3, 2, 7. [Harrison]

77232917 was found on a church computer. [Tryggestad and Ison]