21442924 has 6 divisors (see below), whose sum is σ = 37525124. Its totient is φ = 10721460.

The previous prime is 21442913. The next prime is 21442937. The reversal of 21442924 is 42924412.

It is a junction number, because it is equal to n+sod(n) for n = 21442892 and 21442901.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2680362 + ... + 2680369.

Almost surely, 2^21442924 is an apocalyptic number.

It is an amenable number.

21442924 is a deficient number, since it is larger than the sum of its proper divisors (16082200).

21442924 is a wasteful number, since it uses less digits than its factorization.

21442924 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5360735 (or 5360733 counting only the distinct ones).

The product of its digits is 4608, while the sum is 28.

The square root of 21442924 is about 4630.6504942610. The cubic root of 21442924 is about 277.8186108625.

It can be divided in two parts, 21442 and 924, that added together give a triangular number (22366 = T₂₁₁).

The spelling of 21442924 in words is "twenty-one million, four hundred forty-two thousand, nine hundred twenty-four".