856821659922 has 54 divisors (see below), whose sum is σ = 1959467816007. Its totient is φ = 270551697912.

The previous prime is 856821659851. The next prime is 856821659977. The reversal of 856821659922 is 229956128658.

856821659922 is a `hidden beast` number, since 8 + 5 + 6 + 8 + 2 + 16 + 599 + 22 = 666.

It can be written as a sum of positive squares in only one way, i.e., 428410829961 + 428410829961 = 654531^2 + 654531^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=654531.

It is a super-2 number, since 2×856821659922² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 856821659922.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 74610793 + ... + 74622275.

Almost surely, 2^856821659922 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 856821659922

856821659922 is an abundant number, since it is smaller than the sum of its proper divisors (1102646156085).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

856821659922 is an equidigital number, since it uses as much as digits as its factorization.

856821659922 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23012 (or 11507 counting only the distinct ones).

The product of its digits is 37324800, while the sum is 63.

The spelling of 856821659922 in words is "eight hundred fifty-six billion, eight hundred twenty-one million, six hundred fifty-nine thousand, nine hundred twenty-two".