21133924 has 48 divisors (see below), whose sum is σ = 46327680. Its totient is φ = 8225280.

The previous prime is 21133913. The next prime is 21133939. The reversal of 21133924 is 42933112.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13039 + ... + 14569.

It is an arithmetic number, because the mean of its divisors is an integer number (965160).

Almost surely, 2^21133924 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 21133924, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23163840).

21133924 is an abundant number, since it is smaller than the sum of its proper divisors (25193756).

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

21133924 is a wasteful number, since it uses less digits than its factorization.

21133924 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1588 (or 1586 counting only the distinct ones).

The product of its digits is 1296, while the sum is 25.

The square root of 21133924 is about 4597.1647784259. The cubic root of 21133924 is about 276.4776612682.

The spelling of 21133924 in words is "twenty-one million, one hundred thirty-three thousand, nine hundred twenty-four".