172508209 has 2 divisors, whose sum is σ = 172508210. Its totient is φ = 172508208.

The previous prime is 172508191. The next prime is 172508213. The reversal of 172508209 is 902805271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 105513984 + 66994225 = 10272^2 + 8185^2 .

It is a cyclic number.

It is not a de Polignac number, because 172508209 - 2⁷ = 172508081 is a prime.

It is not a weakly prime, because it can be changed into another prime (172508249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86254104 + 86254105.

It is an arithmetic number, because the mean of its divisors is an integer number (86254105).

Almost surely, 2^172508209 is an apocalyptic number.

It is an amenable number.

172508209 is a deficient number, since it is larger than the sum of its proper divisors (1).

172508209 is an equidigital number, since it uses as much as digits as its factorization.

172508209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 172508209 is about 13134.2380441349. The cubic root of 172508209 is about 556.6769709369.

The spelling of 172508209 in words is "one hundred seventy-two million, five hundred eight thousand, two hundred nine".