4.16**

import java.util.Scanner;public class w{/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubSystem.out.println("请输入一个数：");Scanner input = new Scanner(System.in);        int num=input.nextInt();        int i=2;        System.out.println("The smallest factors are:");        while(num>=i)        {        if(num%i==0)        {        num/=i;                System.out.println(i);        }        else        i++;        }}}