91639808 has 52 divisors (see below), whose sum is σ = 197468628. Its totient is φ = 42270720.

The previous prime is 91639799. The next prime is 91639811. The reversal of 91639808 is 80893619.

It can be written as a sum of positive squares in 2 ways, for example, as 39337984 + 52301824 = 6272^2 + 7232^2 .

It is a tau number, because it is divible by the number of its divisors (52).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52388 + ... + 54108.

Almost surely, 2^91639808 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 91639808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (98734314).

91639808 is an abundant number, since it is smaller than the sum of its proper divisors (105828820).

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

91639808 is a wasteful number, since it uses less digits than its factorization.

91639808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1758 (or 1736 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 44.

The square root of 91639808 is about 9572.8683266824. The cubic root of 91639808 is about 450.8458297401.

The spelling of 91639808 in words is "ninety-one million, six hundred thirty-nine thousand, eight hundred eight".