21815858804 has 24 divisors (see below), whose sum is σ = 40572701568. Its totient is φ = 10228394880.

The previous prime is 21815858783. The next prime is 21815858839. The reversal of 21815858804 is 40885851812.

It is a Smith number, since the sum of its digits (50) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 573494 + ... + 610349.

It is an arithmetic number, because the mean of its divisors is an integer number (1690529232).

Almost surely, 2^21815858804 is an apocalyptic number.

It is an amenable number.

21815858804 is a deficient number, since it is larger than the sum of its proper divisors (18756842764).

21815858804 is a wasteful number, since it uses less digits than its factorization.

21815858804 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1184135 (or 1184133 counting only the distinct ones).

The product of its (nonzero) digits is 819200, while the sum is 50.

The spelling of 21815858804 in words is "twenty-one billion, eight hundred fifteen million, eight hundred fifty-eight thousand, eight hundred four".