91864687021 has 8 divisors (see below), whose sum is σ = 95944190400. Its totient is φ = 87792299232.

The previous prime is 91864687003. The next prime is 91864687027. The reversal of 91864687021 is 12078646819.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 91864687021 - 2²⁷ = 91730469293 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 91864687021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91864687027) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1752496 + ... + 1804153.

It is an arithmetic number, because the mean of its divisors is an integer number (11993023800).

Almost surely, 2^91864687021 is an apocalyptic number.

It is an amenable number.

91864687021 is a deficient number, since it is larger than the sum of its proper divisors (4079503379).

91864687021 is a wasteful number, since it uses less digits than its factorization.

91864687021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3557795.

The product of its (nonzero) digits is 1161216, while the sum is 52.

The spelling of 91864687021 in words is "ninety-one billion, eight hundred sixty-four million, six hundred eighty-seven thousand, twenty-one".