16209 has 6 divisors (see below), whose sum is σ = 23426. Its totient is φ = 10800.

The previous prime is 16193. The next prime is 16217. The reversal of 16209 is 90261.

It can be written as a sum of positive squares in only one way, i.e., 11025 + 5184 = 105^2 + 72^2 .

It is not a de Polignac number, because 16209 - 2⁴ = 16193 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16191 and 16200.

It is not an unprimeable number, because it can be changed into a prime (16229) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 892 + ... + 909.

2¹⁶²⁰⁹ is an apocalyptic number.

It is an amenable number.

16209 is a deficient number, since it is larger than the sum of its proper divisors (7217).

16209 is a wasteful number, since it uses less digits than its factorization.

16209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1807 (or 1804 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

The square root of 16209 is about 127.3145710435. The cubic root of 16209 is about 25.3076648286.

It can be divided in two parts, 16 and 209, that added together give a square (225 = 15²).

The spelling of 16209 in words is "sixteen thousand, two hundred nine".