20640564416 has 28 divisors (see below), whose sum is σ = 43367952888. Its totient is φ = 9713206272.

The previous prime is 20640564407. The next prime is 20640564419. The reversal of 20640564416 is 61446504602.

It is a super-2 number, since 2×20640564416² (a number of 21 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 20640564416.

It is not an unprimeable number, because it can be changed into a prime (20640564419) 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, 9484466 + ... + 9486641.

Almost surely, 2^20640564416 is an apocalyptic number.

It is an amenable number.

20640564416 is an abundant number, since it is smaller than the sum of its proper divisors (22727388472).

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

20640564416 is a wasteful number, since it uses less digits than its factorization.

20640564416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18971136 (or 18971126 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 38.

The spelling of 20640564416 in words is "twenty billion, six hundred forty million, five hundred sixty-four thousand, four hundred sixteen".