import java.util.Scanner;public class Main { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); while (scanner.hasNextLong()) { long num = scanner.nextLong(); long t = num; for (int i=2;i<=t; i++) { while (num % i == 0) { num = num/i; System.out.print(i+ " "); } } } }}原文：http://www.cnblogs.com/bb3q/p/5068167.html