divisors to store the divisors found.x from 1 to √N:
a. If x is a divisor of n, append it to divisors.
b. If x is a divisor of n, decrement k by 1.
c. If k is 0, return x as the kth factor.n is a perfect square, increment k by 1 to account for the duplicate divisor.k is less than or equal to the length of divisors, return n / divisors[-k] as the kth factor.k is greater than the length of divisors, return -1, indicating there are fewer than k factors.