231565161 has 4 divisors (see below), whose sum is σ = 308753552. Its totient is φ = 154376772.

The previous prime is 231565123. The next prime is 231565181. The reversal of 231565161 is 161565132.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 231565161 - 2⁶ = 231565097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (231565121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38594191 + ... + 38594196.

It is an arithmetic number, because the mean of its divisors is an integer number (77188388).

Almost surely, 2^231565161 is an apocalyptic number.

It is an amenable number.

231565161 is a deficient number, since it is larger than the sum of its proper divisors (77188391).

231565161 is an equidigital number, since it uses as much as digits as its factorization.

231565161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77188390.

The product of its digits is 5400, while the sum is 30.

The square root of 231565161 is about 15217.2652273659. The cubic root of 231565161 is about 614.0792275756.

It can be divided in two parts, 2315 and 65161, that added together give a palindrome (67476).

The spelling of 231565161 in words is "two hundred thirty-one million, five hundred sixty-five thousand, one hundred sixty-one".