172813209 has 4 divisors (see below), whose sum is σ = 230417616. Its totient is φ = 115208804.

The previous prime is 172813187. The next prime is 172813213. The reversal of 172813209 is 902318271.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 172813209 - 2⁸ = 172812953 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 172813209.

It is not an unprimeable number, because it can be changed into a prime (172813409) 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, 28802199 + ... + 28802204.

It is an arithmetic number, because the mean of its divisors is an integer number (57604404).

Almost surely, 2^172813209 is an apocalyptic number.

It is an amenable number.

172813209 is a deficient number, since it is larger than the sum of its proper divisors (57604407).

172813209 is an equidigital number, since it uses as much as digits as its factorization.

172813209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57604406.

The product of its (nonzero) digits is 6048, while the sum is 33.

The square root of 172813209 is about 13145.8437918606. The cubic root of 172813209 is about 557.0048519744.

The spelling of 172813209 in words is "one hundred seventy-two million, eight hundred thirteen thousand, two hundred nine".