20564647643256 has 16 divisors (see below), whose sum is σ = 51411619108200. Its totient is φ = 6854882547744.

The previous prime is 20564647643251. The next prime is 20564647643317. The reversal of 20564647643256 is 65234674646502.

It is a self number, because there is not a number n which added to its sum of digits gives 20564647643256.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20564647643251) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 428430159211 + ... + 428430159258.

Almost surely, 2^{20564647643256} is an apocalyptic number.

It is an amenable number.

20564647643256 is an abundant number, since it is smaller than the sum of its proper divisors (30846971464944).

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

20564647643256 is a wasteful number, since it uses less digits than its factorization.

20564647643256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 856860318478 (or 856860318474 counting only the distinct ones).

The product of its (nonzero) digits is 174182400, while the sum is 60.

The spelling of 20564647643256 in words is "twenty trillion, five hundred sixty-four billion, six hundred forty-seven million, six hundred forty-three thousand, two hundred fifty-six".