165309 has 4 divisors (see below), whose sum is σ = 220416. Its totient is φ = 110204.

The previous prime is 165293. The next prime is 165311. The reversal of 165309 is 903561.

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 a cyclic number.

It is not a de Polignac number, because 165309 - 2⁴ = 165293 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165349) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27549 + ... + 27554.

It is an arithmetic number, because the mean of its divisors is an integer number (55104).

2¹⁶⁵³⁰⁹ is an apocalyptic number.

It is an amenable number.

165309 is a deficient number, since it is larger than the sum of its proper divisors (55107).

165309 is an equidigital number, since it uses as much as digits as its factorization.

165309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55106.

The product of its (nonzero) digits is 810, while the sum is 24.

The square root of 165309 is about 406.5820950312. The cubic root of 165309 is about 54.8822826628.

It can be divided in two parts, 165 and 309, that added together give a palindrome (474).

The spelling of 165309 in words is "one hundred sixty-five thousand, three hundred nine".