21612688 has 20 divisors (see below), whose sum is σ = 41974000. Its totient is φ = 10780704.

The previous prime is 21612677. The next prime is 21612691. The reversal of 21612688 is 88621612.

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, 6631 + ... + 9337.

It is an arithmetic number, because the mean of its divisors is an integer number (2098700).

Almost surely, 2^21612688 is an apocalyptic number.

It is an amenable number.

21612688 is a deficient number, since it is larger than the sum of its proper divisors (20361312).

21612688 is a wasteful number, since it uses less digits than its factorization.

21612688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3214 (or 3208 counting only the distinct ones).

The product of its digits is 9216, while the sum is 34.

The square root of 21612688 is about 4648.9448265171. The cubic root of 21612688 is about 278.5498494164.

The spelling of 21612688 in words is "twenty-one million, six hundred twelve thousand, six hundred eighty-eight".