91381920 has 96 divisors (see below), whose sum is σ = 328987008. Its totient is φ = 20886528.

The previous prime is 91381891. The next prime is 91381943. The reversal of 91381920 is 2918319.

It is a tau number, because it is divible by the number of its divisors (96).

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, 10239 + ... + 16958.

It is an arithmetic number, because the mean of its divisors is an integer number (3426948).

Almost surely, 2^91381920 is an apocalyptic number.

It is an amenable number.

91381920 is an abundant number, since it is smaller than the sum of its proper divisors (237605088).

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

91381920 is a wasteful number, since it uses less digits than its factorization.

91381920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27222 (or 27214 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 33.

The square root of 91381920 is about 9559.3891018203. The cubic root of 91381920 is about 450.4225167441.

The spelling of 91381920 in words is "ninety-one million, three hundred eighty-one thousand, nine hundred twenty".