91990392 has 64 divisors (see below), whose sum is σ = 255682560. Its totient is φ = 27388800.

The previous prime is 91990321. The next prime is 91990411. The reversal of 91990392 is 29309919.

It is a happy number.

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, 4917 + ... + 14427.

It is an arithmetic number, because the mean of its divisors is an integer number (3995040).

Almost surely, 2^91990392 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91990392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127841280).

91990392 is an abundant number, since it is smaller than the sum of its proper divisors (163692168).

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

91990392 is a wasteful number, since it uses less digits than its factorization.

91990392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9564 (or 9560 counting only the distinct ones).

The product of its (nonzero) digits is 39366, while the sum is 42.

The square root of 91990392 is about 9591.1621819256. The cubic root of 91990392 is about 451.4200278024.

The spelling of 91990392 in words is "ninety-one million, nine hundred ninety thousand, three hundred ninety-two".