There are 4 unequal natural numbers, the difference between the largest number and the smallest number is equal to 4, the product of the smallest number and the largest number is an odd number, and the sum of these four numbers is the smallest two-digit odd number. What is the product of these four numbers?
有4个互不相等的自然数，最大数与最小数的差等于4，最小数与最大数的积是一个奇数，而这四个数的和是最小的两位奇数．这四个数的积是多少？
<gadget id="calculator">1 * 2 * 3 * 5</gadget>
<output>30</output>

<result>30</result>