There is a four-digit number. The product obtained by multiplying it by 9 is exactly the new four-digit number obtained by reversing the order of the digits of the original four-digit number. Find the original four-digit number.
有一个四位数，它乘以9后所得乘积恰好是将原来的四位数各位数字顺序颠倒而得的新四位数，求原来的四位数．
<result>1_089</result>