91440168731 has 2 divisors, whose sum is σ = 91440168732. Its totient is φ = 91440168730.

The previous prime is 91440168727. The next prime is 91440168737. The reversal of 91440168731 is 13786104419.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 91440168731 - 2² = 91440168727 is a prime.

It is a super-2 number, since 2×91440168731² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (91440168737) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45720084365 + 45720084366.

It is an arithmetic number, because the mean of its divisors is an integer number (45720084366).

Almost surely, 2^91440168731 is an apocalyptic number.

91440168731 is a deficient number, since it is larger than the sum of its proper divisors (1).

91440168731 is an equidigital number, since it uses as much as digits as its factorization.

91440168731 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 145152, while the sum is 44.

The spelling of 91440168731 in words is "ninety-one billion, four hundred forty million, one hundred sixty-eight thousand, seven hundred thirty-one".