91711521 has 20 divisors (see below), whose sum is σ = 149457264. Its totient is φ = 55582200.

The previous prime is 91711513. The next prime is 91711531. The reversal of 91711521 is 12511719.

It is not a de Polignac number, because 91711521 - 2³ = 91711513 is a prime.

It is a super-2 number, since 2×91711521² = 16822006168266882, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (91711531) by changing a digit.

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 19 ways as a sum of consecutive naturals, for example, 50575 + ... + 52356.

Almost surely, 2^91711521 is an apocalyptic number.

It is an amenable number.

91711521 is a deficient number, since it is larger than the sum of its proper divisors (57745743).

91711521 is a wasteful number, since it uses less digits than its factorization.

91711521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102954 (or 102945 counting only the distinct ones).

The product of its digits is 630, while the sum is 27.

The square root of 91711521 is about 9576.6132322445. The cubic root of 91711521 is about 450.9634026511.

The spelling of 91711521 in words is "ninety-one million, seven hundred eleven thousand, five hundred twenty-one".