90991992 has 128 divisors (see below), whose sum is σ = 284981760. Its totient is φ = 23569920.

The previous prime is 90991961. The next prime is 90992017. The reversal of 90991992 is 29919909.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 132883 + ... + 133565.

It is an arithmetic number, because the mean of its divisors is an integer number (2226420).

Almost surely, 2^90991992 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 90991992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (142490880).

90991992 is an abundant number, since it is smaller than the sum of its proper divisors (193989768).

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

90991992 is a wasteful number, since it uses less digits than its factorization.

90991992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 773 (or 769 counting only the distinct ones).

The product of its (nonzero) digits is 118098, while the sum is 48.

The square root of 90991992 is about 9538.9722716863. The cubic root of 90991992 is about 449.7809501789.

The spelling of 90991992 in words is "ninety million, nine hundred ninety-one thousand, nine hundred ninety-two".