20566464656 has 20 divisors (see below), whose sum is σ = 40200161772. Its totient is φ = 10192229376.

The previous prime is 20566464643. The next prime is 20566464679. The reversal of 20566464656 is 65646466502.

It can be written as a sum of positive squares in 2 ways, for example, as 3138240400 + 17428224256 = 56020^2 + 132016^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5685821 + ... + 5689436.

Almost surely, 2^20566464656 is an apocalyptic number.

It is an amenable number.

20566464656 is a deficient number, since it is larger than the sum of its proper divisors (19633697116).

20566464656 is a wasteful number, since it uses less digits than its factorization.

20566464656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11375378 (or 11375372 counting only the distinct ones).

The product of its (nonzero) digits is 6220800, while the sum is 50.

The spelling of 20566464656 in words is "twenty billion, five hundred sixty-six million, four hundred sixty-four thousand, six hundred fifty-six".