165331261 has 2 divisors, whose sum is σ = 165331262. Its totient is φ = 165331260.

The previous prime is 165331253. The next prime is 165331321. The reversal of 165331261 is 162133561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 139004100 + 26327161 = 11790^2 + 5131^2 .

It is a cyclic number.

It is not a de Polignac number, because 165331261 - 2³ = 165331253 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165331211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82665630 + 82665631.

It is an arithmetic number, because the mean of its divisors is an integer number (82665631).

Almost surely, 2^165331261 is an apocalyptic number.

It is an amenable number.

165331261 is a deficient number, since it is larger than the sum of its proper divisors (1).

165331261 is an equidigital number, since it uses as much as digits as its factorization.

165331261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3240, while the sum is 28.

The square root of 165331261 is about 12858.1204302962. The cubic root of 165331261 is about 548.8474608919.

The spelling of 165331261 in words is "one hundred sixty-five million, three hundred thirty-one thousand, two hundred sixty-one".