165509 has 8 divisors (see below), whose sum is σ = 180480. Its totient is φ = 151200.

The previous prime is 165479. The next prime is 165511. The reversal of 165509 is 905561.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-165509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165559) 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 7 ways as a sum of consecutive naturals, for example, 449 + ... + 729.

It is an arithmetic number, because the mean of its divisors is an integer number (22560).

2¹⁶⁵⁵⁰⁹ is an apocalyptic number.

165509 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

165509 is a deficient number, since it is larger than the sum of its proper divisors (14971).

165509 is a wasteful number, since it uses less digits than its factorization.

165509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 331.

The product of its (nonzero) digits is 1350, while the sum is 26.

The square root of 165509 is about 406.8279734728. The cubic root of 165509 is about 54.9044069530.

The spelling of 165509 in words is "one hundred sixty-five thousand, five hundred nine".