21453804 has 18 divisors (see below), whose sum is σ = 54230540. Its totient is φ = 7151256.

The previous prime is 21453799. The next prime is 21453833. The reversal of 21453804 is 40835412.

It is a tau number, because it is divible by the number of its divisors (18).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 297934 + ... + 298005.

Almost surely, 2^21453804 is an apocalyptic number.

It is an amenable number.

21453804 is an abundant number, since it is smaller than the sum of its proper divisors (32776736).

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

21453804 is a wasteful number, since it uses less digits than its factorization.

21453804 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 595949 (or 595944 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 21453804 is about 4631.8251262326. The cubic root of 21453804 is about 277.8655907023.

The spelling of 21453804 in words is "twenty-one million, four hundred fifty-three thousand, eight hundred four".