16561561116 has 24 divisors (see below), whose sum is σ = 38647822864. Its totient is φ = 5519923200.

The previous prime is 16561561099. The next prime is 16561561139. The reversal of 16561561116 is 61116516561.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49116 + ... + 188508.

Almost surely, 2^16561561116 is an apocalyptic number.

It is an amenable number.

16561561116 is an abundant number, since it is smaller than the sum of its proper divisors (22086261748).

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

16561561116 is a wasteful number, since it uses less digits than its factorization.

16561561116 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149301 (or 149299 counting only the distinct ones).

The product of its digits is 32400, while the sum is 39.

The spelling of 16561561116 in words is "sixteen billion, five hundred sixty-one million, five hundred sixty-one thousand, one hundred sixteen".