21243804 has 24 divisors (see below), whose sum is σ = 51168768. Its totient is φ = 6852720.

The previous prime is 21243793. The next prime is 21243821. The reversal of 21243804 is 40834212.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28182 + ... + 28925.

It is an arithmetic number, because the mean of its divisors is an integer number (2132032).

Almost surely, 2^21243804 is an apocalyptic number.

It is an amenable number.

21243804 is an abundant number, since it is smaller than the sum of its proper divisors (29924964).

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

21243804 is a wasteful number, since it uses less digits than its factorization.

21243804 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57145 (or 57143 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 24.

The square root of 21243804 is about 4609.1001290924. The cubic root of 21243804 is about 276.9559896541.

The spelling of 21243804 in words is "twenty-one million, two hundred forty-three thousand, eight hundred four".