91631979 has 10 divisors (see below), whose sum is σ = 136882460. Its totient is φ = 61087932.

The previous prime is 91631971. The next prime is 91631983. The reversal of 91631979 is 97913619.

91631979 is a `hidden beast` number, since 9 + 1 + 631 + 9 + 7 + 9 = 666.

It is not a de Polignac number, because 91631979 - 2³ = 91631971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91631971) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 565549 + ... + 565710.

It is an arithmetic number, because the mean of its divisors is an integer number (13688246).

Almost surely, 2^91631979 is an apocalyptic number.

91631979 is a deficient number, since it is larger than the sum of its proper divisors (45250481).

91631979 is a wasteful number, since it uses less digits than its factorization.

91631979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1131271 (or 1131262 counting only the distinct ones).

The product of its digits is 91854, while the sum is 45.

The square root of 91631979 is about 9572.4594018465. The cubic root of 91631979 is about 450.8329904417.

The spelling of 91631979 in words is "ninety-one million, six hundred thirty-one thousand, nine hundred seventy-nine".