172372309 has 4 divisors (see below), whose sum is σ = 174800160. Its totient is φ = 169944460.

The previous prime is 172372303. The next prime is 172372331. The reversal of 172372309 is 903273271.

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, and also an emirpimes, since its reverse is a distinct semiprime: 903273271 = 347 ⋅2603093.

It is a cyclic number.

It is not a de Polignac number, because 172372309 - 2³ = 172372301 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172372301) 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, 1213819 + ... + 1213960.

It is an arithmetic number, because the mean of its divisors is an integer number (43700040).

Almost surely, 2^172372309 is an apocalyptic number.

It is an amenable number.

172372309 is a deficient number, since it is larger than the sum of its proper divisors (2427851).

172372309 is an equidigital number, since it uses as much as digits as its factorization.

172372309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2427850.

The product of its (nonzero) digits is 15876, while the sum is 34.

The square root of 172372309 is about 13129.0635233439. The cubic root of 172372309 is about 556.5307512767.

The spelling of 172372309 in words is "one hundred seventy-two million, three hundred seventy-two thousand, three hundred nine".