16561560166065 has 12 divisors (see below), whose sum is σ = 28706704287924. Its totient is φ = 8832832088544.

The previous prime is 16561560166051. The next prime is 16561560166091. The reversal of 16561560166065 is 56066106516561.

16561560166065 is a `hidden beast` number, since 1 + 6 + 5 + 6 + 1 + 560 + 16 + 6 + 0 + 65 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 2676963916449 + 13884596249616 = 1636143^2 + 3726204^2 .

It is not a de Polignac number, because 16561560166065 - 2⁶ = 16561560166001 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 184017335134 + ... + 184017335223.

It is an arithmetic number, because the mean of its divisors is an integer number (2392225357327).

Almost surely, 2^{16561560166065} is an apocalyptic number.

16561560166065 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

16561560166065 is a deficient number, since it is larger than the sum of its proper divisors (12145144121859).

16561560166065 is a wasteful number, since it uses less digits than its factorization.

16561560166065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 368034670368 (or 368034670365 counting only the distinct ones).

The product of its (nonzero) digits is 5832000, while the sum is 54.

The spelling of 16561560166065 in words is "sixteen trillion, five hundred sixty-one billion, five hundred sixty million, one hundred sixty-six thousand, sixty-five".