91518021 has 24 divisors (see below), whose sum is σ = 159966144. Its totient is φ = 49219200.

The previous prime is 91517971. The next prime is 91518029. The reversal of 91518021 is 12081519.

It is not a de Polignac number, because 91518021 - 2⁷ = 91517893 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91518029) 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 23 ways as a sum of consecutive naturals, for example, 41655 + ... + 43796.

It is an arithmetic number, because the mean of its divisors is an integer number (6665256).

Almost surely, 2^91518021 is an apocalyptic number.

It is an amenable number.

91518021 is a deficient number, since it is larger than the sum of its proper divisors (68448123).

91518021 is a wasteful number, since it uses less digits than its factorization.

91518021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85481 (or 85478 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 27.

The square root of 91518021 is about 9566.5051612384. The cubic root of 91518021 is about 450.6460202772.

The spelling of 91518021 in words is "ninety-one million, five hundred eighteen thousand, twenty-one".