Achilles Number in Java

An Achilles Number is a number that is powerful but not a perfect power. A Powerful Number is a positive integer N, such that for every prime factor p of N, p2 is also a factor. A Perfect Power is a positive integer N such that it can be expressed as ab, where a and b are natural numbers > 1. 72, 108, 200, 288 are some of the first few Achilles Numbers. The prime factors of 72 = 2 × 2 × 2 × 3 × 3. Both 2 and 22 = 4 are factors of 72. Both 3 and 32 = 9 are factors of 72. Also, 72 can’t be represented as ab. Therefore, 72 is an Achilles Number. Write a program in Java to input an integer from the user and check whether it is an Achilles Number or not. 

 import java.io.*;

 class Power

{ 

 public static boolean isPerfectPower(int num)

{ 

 for(int i = 2; i <= num; i++)

{

 for(int j = 2; j <= num; j++)

{ 

 if(Math.pow(i, j) == num)

{ 

 return true; 

 }

 else if(Math.pow(i, j) > num)

 break; 

 }

 } 

 return false; 

 } 

 public static void main(String args[])throws IOException

{

 BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

 System.out.print("Enter the number: "); 

 int num = Integer.parseInt(br.readLine()); 

 boolean status = true; 

 if(!isPerfectPower(num))

{ 

 int n = num; 

 int pf = 2; 

 while(n != 1)

{ 

 if(n % pf == 0)

{

 int s = pf * pf;

 if(num % s != 0)

{ 

 status = false; 

 break;

 }

 n /= pf; 

 } 

 else

 pf++; 

 }

 } 

 else 

 status = false; 

 if(status)

 System.out.println(num + " is an Achilles Number."); 

 else 

 System.out.println(num + " is not an Achilles Number.");

 } 

}