165561261161323 has 4 divisors (see below), whose sum is σ = 169083841186080. Its totient is φ = 162038681136568.

The previous prime is 165561261161299. The next prime is 165561261161353. The reversal of 165561261161323 is 323161162165561.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 165561261161323 - 2⁴⁵ = 130376889072491 is a prime.

It is a super-2 number, since 2×165561261161323² (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 (165561261161353) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1761290012308 + ... + 1761290012401.

It is an arithmetic number, because the mean of its divisors is an integer number (42270960296520).

Almost surely, 2^{165561261161323} is an apocalyptic number.

165561261161323 is a deficient number, since it is larger than the sum of its proper divisors (3522580024757).

165561261161323 is an equidigital number, since it uses as much as digits as its factorization.

165561261161323 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3522580024756.

The product of its digits is 1166400, while the sum is 49.

The spelling of 165561261161323 in words is "one hundred sixty-five trillion, five hundred sixty-one billion, two hundred sixty-one million, one hundred sixty-one thousand, three hundred twenty-three".