It is known that the single digit of the natural number N is 0, and there are 8 divisors, what is the smallest number of N.
已知自然数N的个位数字是0，且有8个约数，则N最小是多少．
<gadget id="calculator">2 ** 1</gadget>
<output>2</output>

<gadget id="calculator">5 ** 1</gadget>
<output>5</output>

<gadget id="calculator">2 * 5 * 3</gadget>
<output>30</output>

<result>30</result>