21700724 has 24 divisors (see below), whose sum is σ = 39428928. Its totient is φ = 10442880.

The previous prime is 21700711. The next prime is 21700741. The reversal of 21700724 is 42700712.

It is a self number, because there is not a number n which added to its sum of digits gives 21700724.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11324 + ... + 13100.

It is an arithmetic number, because the mean of its divisors is an integer number (1642872).

Almost surely, 2^21700724 is an apocalyptic number.

It is an amenable number.

21700724 is a deficient number, since it is larger than the sum of its proper divisors (17728204).

21700724 is a wasteful number, since it uses less digits than its factorization.

21700724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1895 (or 1893 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 23.

The square root of 21700724 is about 4658.4035892138. The cubic root of 21700724 is about 278.9275472079.

The spelling of 21700724 in words is "twenty-one million, seven hundred thousand, seven hundred twenty-four".