91656995621 has 16 divisors (see below), whose sum is σ = 94748978688. Its totient is φ = 88619184000.

The previous prime is 91656995603. The next prime is 91656995701. The reversal of 91656995621 is 12659965619.

It is a cyclic number.

It is not a de Polignac number, because 91656995621 - 2¹⁴ = 91656979237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91656995021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1248881 + ... + 1320233.

It is an arithmetic number, because the mean of its divisors is an integer number (5921811168).

Almost surely, 2^91656995621 is an apocalyptic number.

It is an amenable number.

91656995621 is a deficient number, since it is larger than the sum of its proper divisors (3091983067).

91656995621 is a wasteful number, since it uses less digits than its factorization.

91656995621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71732.

The product of its digits is 7873200, while the sum is 59.

The spelling of 91656995621 in words is "ninety-one billion, six hundred fifty-six million, nine hundred ninety-five thousand, six hundred twenty-one".