165161 has 2 divisors, whose sum is σ = 165162. Its totient is φ = 165160.

The previous prime is 165133. The next prime is 165173. The reversal of 165161 is 161561.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 105625 + 59536 = 325^2 + 244^2 .

It is an emirp because it is prime and its reverse (161561) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-165161 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 165161.

It is not a weakly prime, because it can be changed into another prime (165181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82580 + 82581.

It is an arithmetic number, because the mean of its divisors is an integer number (82581).

2¹⁶⁵¹⁶¹ is an apocalyptic number.

It is an amenable number.

165161 is a deficient number, since it is larger than the sum of its proper divisors (1).

165161 is an equidigital number, since it uses as much as digits as its factorization.

165161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 180, while the sum is 20.

The square root of 165161 is about 406.4000492126. The cubic root of 165161 is about 54.8658991970.

Subtracting from 165161 its reverse (161561), we obtain a square (3600 = 60²).

It can be divided in two parts, 165 and 161, that multiplied together give a triangular number (26565 = T₂₃₀).

The spelling of 165161 in words is "one hundred sixty-five thousand, one hundred sixty-one".