When Wang Le calculated 6.4 divided by a number, because the decimal point of the quotient was wrong by one place to the right, the result was 40. What is the divisor of this question?
王乐在计算6.4除以一个数时，由于商的小数点向右点错了一位，结果是40，这道题的除数是多少？
<gadget id="calculator">6.4 / 4</gadget>
<output>1.6</output>

<result>1.6</result>