199965590164561 has 27 divisors (see below), whose sum is σ = 222548707476081. Its totient is φ = 179588766281184.

The previous prime is 199965590164559. The next prime is 199965590164573. The reversal of 199965590164561 is 165461095569991.

The square root of 199965590164561 is 14140919.

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

It can be written as a sum of positive squares in 4 ways, for example, as 830593454161 + 199134996710400 = 911369^2 + 14111520^2 .

It is not a de Polignac number, because 199965590164561 - 2¹ = 199965590164559 is a prime.

It is a super-2 number, since 2×199965590164561² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (199965590164531) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 6801767340 + ... + 6801796738.

Almost surely, 2^{199965590164561} is an apocalyptic number.

199965590164561 is the 14140919-th square number.

199965590164561 is the 7070460-th centered octagonal number.

It is an amenable number.

199965590164561 is a deficient number, since it is larger than the sum of its proper divisors (22583117311520).

199965590164561 is an frugal number, since it uses more digits than its factorization.

199965590164561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58898 (or 29449 counting only the distinct ones).

The product of its (nonzero) digits is 708588000, while the sum is 76.

The spelling of 199965590164561 in words is "one hundred ninety-nine trillion, nine hundred sixty-five billion, five hundred ninety million, one hundred sixty-four thousand, five hundred sixty-one".