91321520 has 40 divisors (see below), whose sum is σ = 212917920. Its totient is φ = 36426240.

The previous prime is 91321519. The next prime is 91321547. The reversal of 91321520 is 2512319.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×91321520² = 16679240030220800, which contains 22 as substring.

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 7 ways as a sum of consecutive naturals, for example, 31325 + ... + 34115.

It is an arithmetic number, because the mean of its divisors is an integer number (5322948).

Almost surely, 2^91321520 is an apocalyptic number.

It is an amenable number.

91321520 is an abundant number, since it is smaller than the sum of its proper divisors (121596400).

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

91321520 is a wasteful number, since it uses less digits than its factorization.

91321520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3213 (or 3207 counting only the distinct ones).

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 91321520 is about 9556.2293819267. The cubic root of 91321520 is about 450.3232574444.

Adding to 91321520 its reverse (2512319), we get a palindrome (93833839).

The spelling of 91321520 in words is "ninety-one million, three hundred twenty-one thousand, five hundred twenty".