169209 has 10 divisors (see below), whose sum is σ = 252890. Its totient is φ = 112752.

The previous prime is 169199. The next prime is 169217. The reversal of 169209 is 902961.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 164025 + 5184 = 405^2 + 72^2 .

It is not a de Polignac number, because 169209 - 2⁵ = 169177 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

169209 is a lucky number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 169209.

It is not an unprimeable number, because it can be changed into a prime (169219) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 964 + ... + 1125.

It is an arithmetic number, because the mean of its divisors is an integer number (25289).

2¹⁶⁹²⁰⁹ is an apocalyptic number.

It is an amenable number.

169209 is a deficient number, since it is larger than the sum of its proper divisors (83681).

169209 is an equidigital number, since it uses as much as digits as its factorization.

169209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2101 (or 2092 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 27.

The square root of 169209 is about 411.3502157530. The cubic root of 169209 is about 55.3105299499.

It can be divided in two parts, 169 and 209, that added together give a triangular number (378 = T₂₇).

The spelling of 169209 in words is "one hundred sixty-nine thousand, two hundred nine".