21105924 has 24 divisors (see below), whose sum is σ = 56282688. Its totient is φ = 6030240.

The previous prime is 21105913. The next prime is 21105967. The reversal of 21105924 is 42950112.

It is a junction number, because it is equal to n+sod(n) for n = 21105894 and 21105903.

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, 125547 + ... + 125714.

It is an arithmetic number, because the mean of its divisors is an integer number (2345112).

Almost surely, 2^21105924 is an apocalyptic number.

It is an amenable number.

21105924 is an abundant number, since it is smaller than the sum of its proper divisors (35176764).

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

21105924 is a wasteful number, since it uses less digits than its factorization.

21105924 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 251275 (or 251273 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 21105924 is about 4594.1184137982. The cubic root of 21105924 is about 276.3555070192.

The spelling of 21105924 in words is "twenty-one million, one hundred five thousand, nine hundred twenty-four".