21620624 has 10 divisors (see below), whose sum is σ = 41889990. Its totient is φ = 10810304.

The previous prime is 21620603. The next prime is 21620659. The reversal of 21620624 is 42602612.

It can be written as a sum of positive squares in only one way, i.e., 20539024 + 1081600 = 4532^2 + 1040^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21620624.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 675629 + ... + 675660.

It is an arithmetic number, because the mean of its divisors is an integer number (4188999).

Almost surely, 2^21620624 is an apocalyptic number.

It is an amenable number.

21620624 is a deficient number, since it is larger than the sum of its proper divisors (20269366).

21620624 is a wasteful number, since it uses less digits than its factorization.

21620624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1351297 (or 1351291 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 21620624 is about 4649.7982751943. The cubic root of 21620624 is about 278.5839389767.

The spelling of 21620624 in words is "twenty-one million, six hundred twenty thousand, six hundred twenty-four".