91000031 has 6 divisors (see below), whose sum is σ = 96668160. Its totient is φ = 85646816.

The previous prime is 91000027. The next prime is 91000051. The reversal of 91000031 is 13000019.

It is not a de Polignac number, because 91000031 - 2² = 91000027 is a prime.

It is a super-2 number, since 2×91000031² = 16562011284001922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91000051) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 157151 + ... + 157728.

It is an arithmetic number, because the mean of its divisors is an integer number (16111360).

Almost surely, 2^91000031 is an apocalyptic number.

91000031 is a deficient number, since it is larger than the sum of its proper divisors (5668129).

91000031 is a wasteful number, since it uses less digits than its factorization.

91000031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 314913 (or 314896 counting only the distinct ones).

The product of its (nonzero) digits is 27, while the sum is 14.

The square root of 91000031 is about 9539.3936390108. The cubic root of 91000031 is about 449.7941956031.

The spelling of 91000031 in words is "ninety-one million, thirty-one", and thus it is an aban number and an uban number.