21616604 has 12 divisors (see below), whose sum is σ = 39820200. Its totient is φ = 10239408.

The previous prime is 21616601. The next prime is 21616607. The reversal of 21616604 is 40661612.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21616601) and next prime (21616607).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21616601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 142139 + ... + 142290.

It is an arithmetic number, because the mean of its divisors is an integer number (3318350).

Almost surely, 2^21616604 is an apocalyptic number.

It is an amenable number.

21616604 is a deficient number, since it is larger than the sum of its proper divisors (18203596).

21616604 is a wasteful number, since it uses less digits than its factorization.

21616604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 284452 (or 284450 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 21616604 is about 4649.3659782813. The cubic root of 21616604 is about 278.5666718702.

The spelling of 21616604 in words is "twenty-one million, six hundred sixteen thousand, six hundred four".