21803028 has 48 divisors (see below), whose sum is σ = 55177920. Its totient is φ = 6700512.

The previous prime is 21803003. The next prime is 21803039. The reversal of 21803028 is 82030812.

It is a junction number, because it is equal to n+sod(n) for n = 21802989 and 21803007.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25951 + ... + 26777.

It is an arithmetic number, because the mean of its divisors is an integer number (1149540).

Almost surely, 2^21803028 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 21803028, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27588960).

21803028 is an abundant number, since it is smaller than the sum of its proper divisors (33374892).

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

21803028 is a wasteful number, since it uses less digits than its factorization.

21803028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 873 (or 845 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 21803028 is about 4669.3712638855. The cubic root of 21803028 is about 279.3651774494.

The spelling of 21803028 in words is "twenty-one million, eight hundred three thousand, twenty-eight".