21904800 has 72 divisors (see below), whose sum is σ = 71307936. Its totient is φ = 5840640.

The previous prime is 21904787. The next prime is 21904807. The reversal of 21904800 is 840912.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (21904807) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2164 + ... + 6963.

It is an arithmetic number, because the mean of its divisors is an integer number (990388).

Almost surely, 2^21904800 is an apocalyptic number.

21904800 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21904800 is an abundant number, since it is smaller than the sum of its proper divisors (49403136).

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

21904800 is a wasteful number, since it uses less digits than its factorization.

21904800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9150 (or 9137 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 21904800 is about 4680.2564032326. The cubic root of 21904800 is about 279.7991757252.

The spelling of 21904800 in words is "twenty-one million, nine hundred four thousand, eight hundred".