21556605606 has 32 divisors (see below), whose sum is σ = 45027048960. Its totient is φ = 6867108864.

The previous prime is 21556605589. The next prime is 21556605611. The reversal of 21556605606 is 60650665512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 91375 + ... + 226853.

It is an arithmetic number, because the mean of its divisors is an integer number (1407095280).

Almost surely, 2^21556605606 is an apocalyptic number.

21556605606 is an abundant number, since it is smaller than the sum of its proper divisors (23470443354).

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

21556605606 is a wasteful number, since it uses less digits than its factorization.

21556605606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136660.

The product of its (nonzero) digits is 324000, while the sum is 42.

The spelling of 21556605606 in words is "twenty-one billion, five hundred fifty-six million, six hundred five thousand, six hundred six".