20856133818 has 24 divisors (see below), whose sum is σ = 48664312788. Its totient is φ = 6417271872.

The previous prime is 20856133811. The next prime is 20856133819. The reversal of 20856133818 is 81833165802.

20856133818 is a `hidden beast` number, since 2 + 0 + 8 + 561 + 3 + 3 + 81 + 8 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 18927430929 + 1928702889 = 137577^2 + 43917^2 .

It is not an unprimeable number, because it can be changed into a prime (20856133811) 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, 44564155 + ... + 44564622.

Almost surely, 2^20856133818 is an apocalyptic number.

20856133818 is an abundant number, since it is smaller than the sum of its proper divisors (27808178970).

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

20856133818 is a wasteful number, since it uses less digits than its factorization.

20856133818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89128798 (or 89128795 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 45.

The spelling of 20856133818 in words is "twenty billion, eight hundred fifty-six million, one hundred thirty-three thousand, eight hundred eighteen".