21066724 has 12 divisors (see below), whose sum is σ = 42133504. Its totient is φ = 9028584.

The previous prime is 21066719. The next prime is 21066733. The reversal of 21066724 is 42766012.

21066724 is an admirable number.

It is a Harshad number since it is a multiple of its sum of digits (28), and also a Moran number because the ratio is a prime number: 752383 = 21066724 / (2 + 1 + 0 + 6 + 6 + 7 + 2 + 4).

It is a junction number, because it is equal to n+sod(n) for n = 21066692 and 21066701.

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, 376164 + ... + 376219.

Almost surely, 2^21066724 is an apocalyptic number.

It is an amenable number.

21066724 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21066724 is a wasteful number, since it uses less digits than its factorization.

21066724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 752394 (or 752392 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 28.

The square root of 21066724 is about 4589.8501064850. The cubic root of 21066724 is about 276.1843094352.

The spelling of 21066724 in words is "twenty-one million, sixty-six thousand, seven hundred twenty-four".