21264736 has 24 divisors (see below), whose sum is σ = 42033600. Its totient is φ = 10589568.

The previous prime is 21264709. The next prime is 21264769. The reversal of 21264736 is 63746212.

It is a junction number, because it is equal to n+sod(n) for n = 21264698 and 21264707.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7665 + ... + 10063.

It is an arithmetic number, because the mean of its divisors is an integer number (1751400).

Almost surely, 2^21264736 is an apocalyptic number.

It is an amenable number.

21264736 is a deficient number, since it is larger than the sum of its proper divisors (20768864).

21264736 is a wasteful number, since it uses less digits than its factorization.

21264736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2686 (or 2678 counting only the distinct ones).

The product of its digits is 12096, while the sum is 31.

The square root of 21264736 is about 4611.3702952593. The cubic root of 21264736 is about 277.0469234587.

The spelling of 21264736 in words is "twenty-one million, two hundred sixty-four thousand, seven hundred thirty-six".