16565966357161 has 9 divisors (see below), whose sum is σ = 17938352226231. Its totient is φ = 15291612411192.

The previous prime is 16565966357153. The next prime is 16565966357179. The reversal of 16565966357161 is 16175366956561.

It is a happy number.

The square root of 16565966357161 is 4070131.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 2450586739225 + 14115379617936 = 1565435^2 + 3757044^2 .

It is not a de Polignac number, because 16565966357161 - 2³ = 16565966357153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16565966351161) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 52755160 + ... + 53068246.

It is an arithmetic number, because the mean of its divisors is an integer number (1993150247359).

Almost surely, 2^{16565966357161} is an apocalyptic number.

16565966357161 is the 4070131-st square number.

16565966357161 is the 2035066-th centered octagonal number.

It is an amenable number.

16565966357161 is a deficient number, since it is larger than the sum of its proper divisors (1372385869070).

16565966357161 is an frugal number, since it uses more digits than its factorization.

16565966357161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 626200 (or 313100 counting only the distinct ones).

The product of its digits is 183708000, while the sum is 67.

The spelling of 16565966357161 in words is "sixteen trillion, five hundred sixty-five billion, nine hundred sixty-six million, three hundred fifty-seven thousand, one hundred sixty-one".