21804768 has 48 divisors (see below), whose sum is σ = 63599760. Its totient is φ = 7267968.

The previous prime is 21804737. The next prime is 21804779. The reversal of 21804768 is 86740812.

21804768 is a `hidden beast` number, since 2 + 180 + 476 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 11755 + ... + 13482.

It is an arithmetic number, because the mean of its divisors is an integer number (1324995).

Almost surely, 2^21804768 is an apocalyptic number.

It is an amenable number.

21804768 is an abundant number, since it is smaller than the sum of its proper divisors (41794992).

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

21804768 is a wasteful number, since it uses less digits than its factorization.

21804768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25256 (or 25242 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 21804768 is about 4669.5575807564. The cubic root of 21804768 is about 279.3726088710.

The spelling of 21804768 in words is "twenty-one million, eight hundred four thousand, seven hundred sixty-eight".