20643521204 has 24 divisors (see below), whose sum is σ = 38033436000. Its totient is φ = 9776993760.

The previous prime is 20643521203. The next prime is 20643521207. The reversal of 20643521204 is 40212534602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20643521203) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 587039 + ... + 621209.

It is an arithmetic number, because the mean of its divisors is an integer number (1584726500).

Almost surely, 2^20643521204 is an apocalyptic number.

It is an amenable number.

20643521204 is a deficient number, since it is larger than the sum of its proper divisors (17389914796).

20643521204 is a wasteful number, since it uses less digits than its factorization.

20643521204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42143 (or 42141 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 29.

The spelling of 20643521204 in words is "twenty billion, six hundred forty-three million, five hundred twenty-one thousand, two hundred four".