21736724 has 12 divisors (see below), whose sum is σ = 38967348. Its totient is φ = 10603200.

The previous prime is 21736711. The next prime is 21736753. The reversal of 21736724 is 42763712.

It can be written as a sum of positive squares in 2 ways, for example, as 8179600 + 13557124 = 2860^2 + 3682^2 .

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, 66107 + ... + 66434.

It is an arithmetic number, because the mean of its divisors is an integer number (3247279).

Almost surely, 2^21736724 is an apocalyptic number.

It is an amenable number.

21736724 is a deficient number, since it is larger than the sum of its proper divisors (17230624).

21736724 is a wasteful number, since it uses less digits than its factorization.

21736724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132586 (or 132584 counting only the distinct ones).

The product of its digits is 14112, while the sum is 32.

The square root of 21736724 is about 4662.2659726790. The cubic root of 21736724 is about 279.0817024971.

The spelling of 21736724 in words is "twenty-one million, seven hundred thirty-six thousand, seven hundred twenty-four".