21803008 has 26 divisors (see below), whose sum is σ = 43608884. Its totient is φ = 10899456.

The previous prime is 21803003. The next prime is 21803039. The reversal of 21803008 is 80030812.

It is a self number, because there is not a number n which added to its sum of digits gives 21803008.

It is not an unprimeable number, because it can be changed into a prime (21803003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1435 + ... + 6757.

Almost surely, 2^21803008 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21803008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21804442).

21803008 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21803008 is an frugal number, since it uses more digits than its factorization.

21803008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5347 (or 5325 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 21803008 is about 4669.3691222691. The cubic root of 21803008 is about 279.3650920285.

The spelling of 21803008 in words is "twenty-one million, eight hundred three thousand, eight".