number multiplied by 2 is a multiple of 4, multiplied by 3 is a multiple of 9, multiplied by 4 is a multiple of 16, multiplied by 5 is a multiple of 25, multiplied by 6 is a multiple of 36, multiplied by 7 is a multiple of 49, multiplied by 8 is a multiple of 64 , multiplied by 9 is a multiple of 81. What is the smallest number?
一个数乘2是4的倍数，乘3是9的倍数，乘4是16的倍数，乘5是25的倍数，乘6是36的倍数，乘7是49的倍数，乘8是64的倍数，乘9是81的倍数．这个数最小是多少？
<gadget id="calculator">5 * 7 * 8 * 9</gadget>
<output>2_520</output>

<result>2_520</result>