21696724 has 24 divisors (see below), whose sum is σ = 44108288. Its totient is φ = 9145440.

The previous prime is 21696721. The next prime is 21696757. The reversal of 21696724 is 42769612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21696721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4644 + ... + 8059.

Almost surely, 2^21696724 is an apocalyptic number.

It is an amenable number.

21696724 is an abundant number, since it is smaller than the sum of its proper divisors (22411564).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21696724 is a wasteful number, since it uses less digits than its factorization.

21696724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12775 (or 12773 counting only the distinct ones).

The product of its digits is 36288, while the sum is 37.

The square root of 21696724 is about 4657.9742377991. The cubic root of 21696724 is about 278.9104083212.

The spelling of 21696724 in words is "twenty-one million, six hundred ninety-six thousand, seven hundred twenty-four".