165321 has 20 divisors (see below), whose sum is σ = 267652. Its totient is φ = 101088.

The previous prime is 165317. The next prime is 165331. The reversal of 165321 is 123561.

It can be written as a sum of positive squares in 2 ways, for example, as 35721 + 129600 = 189^2 + 360^2 .

It is not a de Polignac number, because 165321 - 2² = 165317 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 165294 and 165303.

It is not an unprimeable number, because it can be changed into a prime (165311) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 975 + ... + 1131.

2¹⁶⁵³²¹ is an apocalyptic number.

It is an amenable number.

165321 is a deficient number, since it is larger than the sum of its proper divisors (102331).

165321 is a wasteful number, since it uses less digits than its factorization.

165321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182 (or 173 counting only the distinct ones).

The product of its digits is 180, while the sum is 18.

The square root of 165321 is about 406.5968519308. The cubic root of 165321 is about 54.8836106233.

Adding to 165321 its reverse (123561), we get a palindrome (288882).

The spelling of 165321 in words is "one hundred sixty-five thousand, three hundred twenty-one".