91768521 has 12 divisors (see below), whose sum is σ = 132494928. Its totient is φ = 56472624.

The previous prime is 91768489. The next prime is 91768531. The reversal of 91768521 is 12586719.

It is not a de Polignac number, because 91768521 - 2⁵ = 91768489 is a prime.

It is a super-2 number, since 2×91768521² = 16842922893054882, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 91768521.

It is not an unprimeable number, because it can be changed into a prime (91768531) 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 11 ways as a sum of consecutive naturals, for example, 89995 + ... + 91008.

It is an arithmetic number, because the mean of its divisors is an integer number (11041244).

Almost surely, 2^91768521 is an apocalyptic number.

It is an amenable number.

91768521 is a deficient number, since it is larger than the sum of its proper divisors (40726407).

91768521 is a wasteful number, since it uses less digits than its factorization.

91768521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181032 (or 181019 counting only the distinct ones).

The product of its digits is 30240, while the sum is 39.

The square root of 91768521 is about 9579.5887698794. The cubic root of 91768521 is about 451.0568100012.

The spelling of 91768521 in words is "ninety-one million, seven hundred sixty-eight thousand, five hundred twenty-one".