21664423804 has 6 divisors (see below), whose sum is σ = 37912741664. Its totient is φ = 10832211900.

The previous prime is 21664423799. The next prime is 21664423831. The reversal of 21664423804 is 40832446612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2708052972 + ... + 2708052979.

Almost surely, 2^21664423804 is an apocalyptic number.

It is an amenable number.

21664423804 is a deficient number, since it is larger than the sum of its proper divisors (16248317860).

21664423804 is a wasteful number, since it uses less digits than its factorization.

21664423804 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5416105955 (or 5416105953 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 40.

The spelling of 21664423804 in words is "twenty-one billion, six hundred sixty-four million, four hundred twenty-three thousand, eight hundred four".