91631009 has 16 divisors (see below), whose sum is σ = 96953856. Its totient is φ = 86486400.

The previous prime is 91630999. The next prime is 91631017. The reversal of 91631009 is 90013619.

It is a cyclic number.

It is not a de Polignac number, because 91631009 - 2⁸ = 91630753 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (91631809) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 325949 + ... + 326229.

It is an arithmetic number, because the mean of its divisors is an integer number (6059616).

Almost surely, 2^91631009 is an apocalyptic number.

It is an amenable number.

91631009 is a deficient number, since it is larger than the sum of its proper divisors (5322847).

91631009 is a wasteful number, since it uses less digits than its factorization.

91631009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 536.

The product of its (nonzero) digits is 1458, while the sum is 29.

The square root of 91631009 is about 9572.4087355273. The cubic root of 91631009 is about 450.8313996232.

The spelling of 91631009 in words is "ninety-one million, six hundred thirty-one thousand, nine".