21904323820 has 12 divisors (see below), whose sum is σ = 45999080064. Its totient is φ = 8761729520.

The previous prime is 21904323803. The next prime is 21904323871. The reversal of 21904323820 is 2832340912.

It is a happy number.

It is a super-2 number, since 2×21904323820² (a number of 21 digits) contains 22 as substring.

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, 547608076 + ... + 547608115.

It is an arithmetic number, because the mean of its divisors is an integer number (3833256672).

Almost surely, 2^21904323820 is an apocalyptic number.

21904323820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21904323820 is an abundant number, since it is smaller than the sum of its proper divisors (24094756244).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21904323820 is a wasteful number, since it uses less digits than its factorization.

21904323820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1095216200 (or 1095216198 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 34.

The spelling of 21904323820 in words is "twenty-one billion, nine hundred four million, three hundred twenty-three thousand, eight hundred twenty".