91664720 has 80 divisors (see below), whose sum is σ = 245127168. Its totient is φ = 31226880.

The previous prime is 91664717. The next prime is 91664743. The reversal of 91664720 is 2746619.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 106532 + ... + 107388.

Almost surely, 2^91664720 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 91664720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122563584).

91664720 is an abundant number, since it is smaller than the sum of its proper divisors (153462448).

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

91664720 is a wasteful number, since it uses less digits than its factorization.

91664720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1068 (or 1062 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 91664720 is about 9574.1694156726. The cubic root of 91664720 is about 450.8866797229.

The spelling of 91664720 in words is "ninety-one million, six hundred sixty-four thousand, seven hundred twenty".