165761 has 4 divisors (see below), whose sum is σ = 172992. Its totient is φ = 158532.

The previous prime is 165749. The next prime is 165779. The reversal of 165761 is 167561.

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, and also an emirpimes, since its reverse is a distinct semiprime: 167561 = 19 ⋅8819.

It is a cyclic number.

It is not a de Polignac number, because 165761 - 2¹⁴ = 149377 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 165761.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 165761.

It is not an unprimeable number, because it can be changed into a prime (165701) 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 in 3 ways as a sum of consecutive naturals, for example, 3581 + ... + 3626.

It is an arithmetic number, because the mean of its divisors is an integer number (43248).

2¹⁶⁵⁷⁶¹ is an apocalyptic number.

It is an amenable number.

165761 is a deficient number, since it is larger than the sum of its proper divisors (7231).

165761 is an equidigital number, since it uses as much as digits as its factorization.

165761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7230.

The product of its digits is 1260, while the sum is 26.

The square root of 165761 is about 407.1375688880. The cubic root of 165761 is about 54.9322581966.

The spelling of 165761 in words is "one hundred sixty-five thousand, seven hundred sixty-one".