21028944 has 40 divisors (see below), whose sum is σ = 56201760. Its totient is φ = 6767488.

The previous prime is 21028939. The next prime is 21028979. The reversal of 21028944 is 44982012.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 6162 + ... + 8945.

It is an arithmetic number, because the mean of its divisors is an integer number (1405044).

Almost surely, 2^21028944 is an apocalyptic number.

21028944 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21028944 is an abundant number, since it is smaller than the sum of its proper divisors (35172816).

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

21028944 is a wasteful number, since it uses less digits than its factorization.

21028944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15147 (or 15141 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 21028944 is about 4585.7326568390. The cubic root of 21028944 is about 276.0191123081.

The spelling of 21028944 in words is "twenty-one million, twenty-eight thousand, nine hundred forty-four".