21264724 has 24 divisors (see below), whose sum is σ = 42187040. Its totient is φ = 9297504.

The previous prime is 21264709. The next prime is 21264769. The reversal of 21264724 is 42746212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21264692 and 21264701.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 9774 + ... + 11749.

Almost surely, 2^21264724 is an apocalyptic number.

It is an amenable number.

21264724 is a deficient number, since it is larger than the sum of its proper divisors (20922316).

21264724 is a wasteful number, since it uses less digits than its factorization.

21264724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21559 (or 21557 counting only the distinct ones).

The product of its digits is 5376, while the sum is 28.

The square root of 21264724 is about 4611.3689941274. The cubic root of 21264724 is about 277.0468713448.

The spelling of 21264724 in words is "twenty-one million, two hundred sixty-four thousand, seven hundred twenty-four".