Prime checker O(sqrt(n)) algorithm

public class Prime{

    static int complexity = 0;
     public static void main(String []args){

        System.out.println(primality(991567)); // true
        System.out.println(primality(991568));  // false
        System.out.println(primality(991693));  // true

        System.out.println("Complexity: " + complexity);

     }

     static String primality(int n) {
        if(n <= 1){
            complexity++;
            return "Not prime";
        }

        int sqrt = (int)Math.sqrt(n);
        for(int i = 2; i <= sqrt; i++){
            complexity++;
            if(n % i == 0){
                return "Not prime";
            }
        }
        return "Prime";
    }


}