21804800 has 54 divisors (see below), whose sum is σ = 53986128. Its totient is φ = 8719360.

The previous prime is 21804793. The next prime is 21804817. The reversal of 21804800 is 840812.

It is a congruent number.

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, 4697 + ... + 8103.

Almost surely, 2^21804800 is an apocalyptic number.

21804800 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21804800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26993064).

21804800 is an abundant number, since it is smaller than the sum of its proper divisors (32181328).

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

21804800 is an equidigital number, since it uses as much as digits as its factorization.

21804800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3433 (or 3414 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 23.

The square root of 21804800 is about 4669.5610072040. The cubic root of 21804800 is about 279.3727455371.

The spelling of 21804800 in words is "twenty-one million, eight hundred four thousand, eight hundred".