172909 has 6 divisors (see below), whose sum is σ = 190190. Its totient is φ = 157080.

The previous prime is 172883. The next prime is 172933. The reversal of 172909 is 909271.

It can be written as a sum of positive squares in only one way, i.e., 108900 + 64009 = 330^2 + 253^2 .

It is not a de Polignac number, because 172909 - 2⁵ = 172877 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172969) 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, 594 + ... + 835.

2¹⁷²⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

172909 is a deficient number, since it is larger than the sum of its proper divisors (17281).

172909 is a wasteful number, since it uses less digits than its factorization.

172909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1451 (or 1440 counting only the distinct ones).

The product of its (nonzero) digits is 1134, while the sum is 28.

The square root of 172909 is about 415.8232797716. The cubic root of 172909 is about 55.7107749580.

It can be divided in two parts, 172 and 909, that added together give a triangular number (1081 = T₄₆).

The spelling of 172909 in words is "one hundred seventy-two thousand, nine hundred nine".