91239672731 has 2 divisors, whose sum is σ = 91239672732. Its totient is φ = 91239672730.

The previous prime is 91239672721. The next prime is 91239672743. The reversal of 91239672731 is 13727693219.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 91239672731 - 2²² = 91235478427 is a prime.

It is a super-2 number, since 2×91239672731² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 91239672731.

It is not a weakly prime, because it can be changed into another prime (91239672721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45619836365 + 45619836366.

It is an arithmetic number, because the mean of its divisors is an integer number (45619836366).

Almost surely, 2^91239672731 is an apocalyptic number.

91239672731 is a deficient number, since it is larger than the sum of its proper divisors (1).

91239672731 is an equidigital number, since it uses as much as digits as its factorization.

91239672731 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 857304, while the sum is 50.

The spelling of 91239672731 in words is "ninety-one billion, two hundred thirty-nine million, six hundred seventy-two thousand, seven hundred thirty-one".