807921891 has 32 divisors (see below), whose sum is σ = 1374848000. Its totient is φ = 459328320.

The previous prime is 807921887. The next prime is 807921911. The reversal of 807921891 is 198129708.

807921891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 807921891 - 2² = 807921887 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (807921811) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 26871 + ... + 48351.

It is an arithmetic number, because the mean of its divisors is an integer number (42964000).

Almost surely, 2^807921891 is an apocalyptic number.

807921891 is a deficient number, since it is larger than the sum of its proper divisors (566926109).

807921891 is a wasteful number, since it uses less digits than its factorization.

807921891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21696 (or 21690 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 45.

The square root of 807921891 is about 28423.9668413823. The cubic root of 807921891 is about 931.3718878580.

The spelling of 807921891 in words is "eight hundred seven million, nine hundred twenty-one thousand, eight hundred ninety-one".