黑洞数又称陷阱数，是类具有奇特转换特性的整数。

任何一个数字不全相同整数，经有限次“重排求差”操作，总会得某一个或一些数，这些数即为黑洞数。\"重排求差\"操作即组成该数得排后的最大数去重排的最小数。

印度数学家研究过四位黑洞数，得到的黑洞数为6174。用这个程序验证这一下这个黑洞数。-few black hole known as traps, and are kind of peculiar characteristics of the integer conversion. Any incomplete figures the same integer, limited by the "rearrangement Difference" operation, in a Federation or a few, These few black hole shall be few. "Rearrangement Difference" operation that is composed of several in the row after the largest number of rearrangement to the smallest number. Indian mathematician studied for four black hole, the black hole at 6,174. Use this to verify this number into the black hole.