172439909 has 2 divisors, whose sum is σ = 172439910. Its totient is φ = 172439908.

The previous prime is 172439893. The next prime is 172439923. The reversal of 172439909 is 909934271.

172439909 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 91259809 + 81180100 = 9553^2 + 9010^2 .

It is a cyclic number.

It is not a de Polignac number, because 172439909 - 2⁴ = 172439893 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 172439909.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (172439989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86219954 + 86219955.

It is an arithmetic number, because the mean of its divisors is an integer number (86219955).

Almost surely, 2^172439909 is an apocalyptic number.

It is an amenable number.

172439909 is a deficient number, since it is larger than the sum of its proper divisors (1).

172439909 is an equidigital number, since it uses as much as digits as its factorization.

172439909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 122472, while the sum is 44.

The square root of 172439909 is about 13131.6377120297. The cubic root of 172439909 is about 556.6034941320.

The spelling of 172439909 in words is "one hundred seventy-two million, four hundred thirty-nine thousand, nine hundred nine".