21566556222 has 64 divisors (see below), whose sum is σ = 45331384320. Its totient is φ = 6831273600.

The previous prime is 21566556199. The next prime is 21566556239. The reversal of 21566556222 is 22265566512.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8769229 + ... + 8771687.

It is an arithmetic number, because the mean of its divisors is an integer number (708302880).

Almost surely, 2^21566556222 is an apocalyptic number.

21566556222 is an abundant number, since it is smaller than the sum of its proper divisors (23764828098).

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

21566556222 is a wasteful number, since it uses less digits than its factorization.

21566556222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3329.

The product of its digits is 432000, while the sum is 42.

The spelling of 21566556222 in words is "twenty-one billion, five hundred sixty-six million, five hundred fifty-six thousand, two hundred twenty-two".