172171309 has 2 divisors, whose sum is σ = 172171310. Its totient is φ = 172171308.

The previous prime is 172171297. The next prime is 172171313. The reversal of 172171309 is 903171271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 171872100 + 299209 = 13110^2 + 547^2 .

It is a cyclic number.

It is not a de Polignac number, because 172171309 - 2⁹ = 172170797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (172171009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86085654 + 86085655.

It is an arithmetic number, because the mean of its divisors is an integer number (86085655).

Almost surely, 2^172171309 is an apocalyptic number.

It is an amenable number.

172171309 is a deficient number, since it is larger than the sum of its proper divisors (1).

172171309 is an equidigital number, since it uses as much as digits as its factorization.

172171309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2646, while the sum is 31.

The square root of 172171309 is about 13121.4065175956. The cubic root of 172171309 is about 556.3143472419.

The spelling of 172171309 in words is "one hundred seventy-two million, one hundred seventy-one thousand, three hundred nine".