21616624 has 10 divisors (see below), whose sum is σ = 41882240. Its totient is φ = 10808304.

The previous prime is 21616607. The next prime is 21616643. The reversal of 21616624 is 42661612.

It is a junction number, because it is equal to n+sod(n) for n = 21616592 and 21616601.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 675504 + ... + 675535.

It is an arithmetic number, because the mean of its divisors is an integer number (4188224).

Almost surely, 2^21616624 is an apocalyptic number.

It is an amenable number.

21616624 is a deficient number, since it is larger than the sum of its proper divisors (20265616).

21616624 is a wasteful number, since it uses less digits than its factorization.

21616624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1351047 (or 1351041 counting only the distinct ones).

The product of its digits is 3456, while the sum is 28.

The square root of 21616624 is about 4649.3681291117. The cubic root of 21616624 is about 278.5667577815.

The spelling of 21616624 in words is "twenty-one million, six hundred sixteen thousand, six hundred twenty-four".