172127209 has 4 divisors (see below), whose sum is σ = 178062660. Its totient is φ = 166191760.

The previous prime is 172127203. The next prime is 172127231. The reversal of 172127209 is 902721271.

It is a happy number.

172127209 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 902721271 = 31 ⋅29120041.

It can be written as a sum of positive squares in 2 ways, for example, as 128936025 + 43191184 = 11355^2 + 6572^2 .

It is a cyclic number.

It is not a de Polignac number, because 172127209 - 2²⁷ = 37909481 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (172127203) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2967682 + ... + 2967739.

It is an arithmetic number, because the mean of its divisors is an integer number (44515665).

Almost surely, 2^172127209 is an apocalyptic number.

It is an amenable number.

172127209 is a deficient number, since it is larger than the sum of its proper divisors (5935451).

172127209 is an equidigital number, since it uses as much as digits as its factorization.

172127209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5935450.

The product of its (nonzero) digits is 3528, while the sum is 31.

The square root of 172127209 is about 13119.7259498817. The cubic root of 172127209 is about 556.2668450228.

The spelling of 172127209 in words is "one hundred seventy-two million, one hundred twenty-seven thousand, two hundred nine".