If a number (except 0) is divided by 1 (1/14), (10/21), (20/49), the resulting quotients are all natural numbers. What is the smallest number?
一个数(0除外)分别除以1(1/14)、(10/21)、(20/49)，所得的商都是自然数，这个数最小是多少．
<result>60</result>