91000815 has 16 divisors (see below), whose sum is σ = 145766400. Its totient is φ = 48478752.

The previous prime is 91000799. The next prime is 91000831. The reversal of 91000815 is 51800019.

It is an interprime number because it is at equal distance from previous prime (91000799) and next prime (91000831).

It is not a de Polignac number, because 91000815 - 2⁴ = 91000799 is a prime.

It is a super-2 number, since 2×91000815² = 16562296661328450, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12666 + ... + 18504.

It is an arithmetic number, because the mean of its divisors is an integer number (9110400).

Almost surely, 2^91000815 is an apocalyptic number.

91000815 is a deficient number, since it is larger than the sum of its proper divisors (54765585).

91000815 is a wasteful number, since it uses less digits than its factorization.

91000815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6886.

The product of its (nonzero) digits is 360, while the sum is 24.

The square root of 91000815 is about 9539.4347316809. The cubic root of 91000815 is about 449.7954873156.

The spelling of 91000815 in words is "ninety-one million, eight hundred fifteen", and thus it is an aban number.