91990812 has 24 divisors (see below), whose sum is σ = 216090000. Its totient is φ = 30457216.

The previous prime is 91990807. The next prime is 91990817. The reversal of 91990812 is 21809919.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (91990807) and next prime (91990817).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91990817) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23937 + ... + 27512.

It is an arithmetic number, because the mean of its divisors is an integer number (9003750).

Almost surely, 2^91990812 is an apocalyptic number.

It is an amenable number.

91990812 is an abundant number, since it is smaller than the sum of its proper divisors (124099188).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

91990812 is a wasteful number, since it uses less digits than its factorization.

91990812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51605 (or 51603 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 39.

The square root of 91990812 is about 9591.1840770574. The cubic root of 91990812 is about 451.4207148166.

The spelling of 91990812 in words is "ninety-one million, nine hundred ninety thousand, eight hundred twelve".