20640405590 has 32 divisors (see below), whose sum is σ = 42694876224. Its totient is φ = 7037608320.

The previous prime is 20640405559. The next prime is 20640405629. The reversal of 20640405590 is 9550404602.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 20640405590.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 801869 + ... + 827208.

It is an arithmetic number, because the mean of its divisors is an integer number (1334214882).

Almost surely, 2^20640405590 is an apocalyptic number.

20640405590 is an abundant number, since it is smaller than the sum of its proper divisors (22054470634).

20640405590 is a wasteful number, since it uses less digits than its factorization.

20640405590 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1629272.

The product of its (nonzero) digits is 43200, while the sum is 35.

The spelling of 20640405590 in words is "twenty billion, six hundred forty million, four hundred five thousand, five hundred ninety".