16561566606 has 16 divisors (see below), whose sum is σ = 35671066704. Its totient is φ = 5095866624.

The previous prime is 16561566533. The next prime is 16561566611. The reversal of 16561566606 is 60666516561.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 106163811 + ... + 106163966.

It is an arithmetic number, because the mean of its divisors is an integer number (2229441669).

Almost surely, 2^16561566606 is an apocalyptic number.

16561566606 is an abundant number, since it is smaller than the sum of its proper divisors (19109500098).

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

16561566606 is a wasteful number, since it uses less digits than its factorization.

16561566606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212327795.

The product of its (nonzero) digits is 1166400, while the sum is 48.

It can be divided in two parts, 165615 and 66606, that added together give a triangular number (232221 = T₆₈₁).

The spelling of 16561566606 in words is "sixteen billion, five hundred sixty-one million, five hundred sixty-six thousand, six hundred six".