165909 has 8 divisors (see below), whose sum is σ = 228960. Its totient is φ = 106736.

The previous prime is 165901. The next prime is 165931. The reversal of 165909 is 909561.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 165909 - 2³ = 165901 is a prime.

It is a Curzon number.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 867 + ... + 1040.

It is an arithmetic number, because the mean of its divisors is an integer number (28620).

2¹⁶⁵⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

165909 is a deficient number, since it is larger than the sum of its proper divisors (63051).

165909 is a wasteful number, since it uses less digits than its factorization.

165909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1939.

The product of its (nonzero) digits is 2430, while the sum is 30.

The square root of 165909 is about 407.3192850824. The cubic root of 165909 is about 54.9486021210.

The spelling of 165909 in words is "one hundred sixty-five thousand, nine hundred nine".