21606612 has 12 divisors (see below), whose sum is σ = 50415456. Its totient is φ = 7202200.

The previous prime is 21606589. The next prime is 21606623. The reversal of 21606612 is 21660612.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 900264 + ... + 900287.

It is an arithmetic number, because the mean of its divisors is an integer number (4201288).

Almost surely, 2^21606612 is an apocalyptic number.

It is an amenable number.

21606612 is an abundant number, since it is smaller than the sum of its proper divisors (28808844).

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

21606612 is a wasteful number, since it uses less digits than its factorization.

21606612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1800558 (or 1800556 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 21606612 is about 4648.2912989614. The cubic root of 21606612 is about 278.5237439560.

The spelling of 21606612 in words is "twenty-one million, six hundred six thousand, six hundred twelve".