91857934021 has 8 divisors (see below), whose sum is σ = 105001713920. Its totient is φ = 78719458608.

The previous prime is 91857933971. The next prime is 91857934123. The reversal of 91857934021 is 12043975819.

It is a happy number.

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

It is not a de Polignac number, because 91857934021 - 2⁹ = 91857933509 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 (91857934321) 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, 1288941 + ... + 1358338.

It is an arithmetic number, because the mean of its divisors is an integer number (13125214240).

Almost surely, 2^91857934021 is an apocalyptic number.

It is an amenable number.

91857934021 is a deficient number, since it is larger than the sum of its proper divisors (13143779899).

91857934021 is a wasteful number, since it uses less digits than its factorization.

91857934021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2652243.

The product of its (nonzero) digits is 544320, while the sum is 49.

The spelling of 91857934021 in words is "ninety-one billion, eight hundred fifty-seven million, nine hundred thirty-four thousand, twenty-one".