91815812 has 12 divisors (see below), whose sum is σ = 175284816. Its totient is φ = 41734440.

The previous prime is 91815803. The next prime is 91815817. The reversal of 91815812 is 21851819.

It is not an unprimeable number, because it can be changed into a prime (91815817) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1043318 + ... + 1043405.

It is an arithmetic number, because the mean of its divisors is an integer number (14607068).

Almost surely, 2^91815812 is an apocalyptic number.

It is an amenable number.

91815812 is a deficient number, since it is larger than the sum of its proper divisors (83469004).

91815812 is a wasteful number, since it uses less digits than its factorization.

91815812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2086738 (or 2086736 counting only the distinct ones).

The product of its digits is 5760, while the sum is 35.

The square root of 91815812 is about 9582.0567729481. The cubic root of 91815812 is about 451.1342776131.

The spelling of 91815812 in words is "ninety-one million, eight hundred fifteen thousand, eight hundred twelve".