91981536 has 24 divisors (see below), whose sum is σ = 241451784. Its totient is φ = 30660480.

The previous prime is 91981529. The next prime is 91981537. The reversal of 91981536 is 63518919.

It is a tau number, because it is divible by the number of its divisors (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91981537) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 478975 + ... + 479166.

It is an arithmetic number, because the mean of its divisors is an integer number (10060491).

Almost surely, 2^91981536 is an apocalyptic number.

91981536 is a gapful number since it is divisible by the number (96) formed by its first and last digit.

It is an amenable number.

91981536 is an abundant number, since it is smaller than the sum of its proper divisors (149470248).

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

91981536 is a wasteful number, since it uses less digits than its factorization.

91981536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 958154 (or 958146 counting only the distinct ones).

The product of its digits is 58320, while the sum is 42.

The square root of 91981536 is about 9590.7004957928. The cubic root of 91981536 is about 451.4055411298.

The spelling of 91981536 in words is "ninety-one million, nine hundred eighty-one thousand, five hundred thirty-six".