856503891 has 12 divisors (see below), whose sum is σ = 1237431832. Its totient is φ = 570882816.

The previous prime is 856503887. The next prime is 856503919. The reversal of 856503891 is 198305658.

856503891 is a `hidden beast` number, since 8 + 56 + 503 + 8 + 91 = 666.

856503891 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 856503891 - 2² = 856503887 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (856503821) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 64755 + ... + 76851.

Almost surely, 2^856503891 is an apocalyptic number.

856503891 is a deficient number, since it is larger than the sum of its proper divisors (380927941).

856503891 is a wasteful number, since it uses less digits than its factorization.

856503891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19970 (or 19967 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 45.

The square root of 856503891 is about 29266.0877296573. The cubic root of 856503891 is about 949.6781517313.

The spelling of 856503891 in words is "eight hundred fifty-six million, five hundred three thousand, eight hundred ninety-one".