21559906204 has 12 divisors (see below), whose sum is σ = 37765403928. Its totient is φ = 10769790800.

The previous prime is 21559906183. The next prime is 21559906217. The reversal of 21559906204 is 40260995512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2535802 + ... + 2544289.

It is an arithmetic number, because the mean of its divisors is an integer number (3147116994).

Almost surely, 2^21559906204 is an apocalyptic number.

It is an amenable number.

21559906204 is a deficient number, since it is larger than the sum of its proper divisors (16205497724).

21559906204 is a wasteful number, since it uses less digits than its factorization.

21559906204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5081156 (or 5081154 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 43.

The spelling of 21559906204 in words is "twenty-one billion, five hundred fifty-nine million, nine hundred six thousand, two hundred four".