20640640624 has 20 divisors (see below), whose sum is σ = 41072086744. Its totient is φ = 10041392448.

The previous prime is 20640640591. The next prime is 20640640639. The reversal of 20640640624 is 42604604602.

It is a self number, because there is not a number n which added to its sum of digits gives 20640640624.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17432382 + ... + 17433565.

Almost surely, 2^20640640624 is an apocalyptic number.

It is an amenable number.

20640640624 is a deficient number, since it is larger than the sum of its proper divisors (20431446120).

20640640624 is a wasteful number, since it uses less digits than its factorization.

20640640624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34865992 (or 34865986 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 34.

The spelling of 20640640624 in words is "twenty billion, six hundred forty million, six hundred forty thousand, six hundred twenty-four".