172209 has 8 divisors (see below), whose sum is σ = 231840. Its totient is φ = 113696.

The previous prime is 172199. The next prime is 172213. The reversal of 172209 is 902271.

It is a happy number.

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 172209 - 2⁹ = 171697 is a prime.

172209 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (172219) 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, 202 + ... + 620.

It is an arithmetic number, because the mean of its divisors is an integer number (28980).

2¹⁷²²⁰⁹ is an apocalyptic number.

It is an amenable number.

172209 is a deficient number, since it is larger than the sum of its proper divisors (59631).

172209 is a wasteful number, since it uses less digits than its factorization.

172209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 559.

The product of its (nonzero) digits is 252, while the sum is 21.

The square root of 172209 is about 414.9807224438. The cubic root of 172209 is about 55.6354939592.

The spelling of 172209 in words is "one hundred seventy-two thousand, two hundred nine".