7. (10 points) It is known that a five-digit palindrome is equal to the product of 45 and a four-digit palindrome (i.e., $\overline{\mathrm{abcba}}=45 \times \overline{\text { deed }}$). Therefore, the largest possible value of this five-digit palindrome is $\qquad$
【Solution】Solution: According to the analysis, we know that, $\overline{\mathrm{abcba}}=45 \overline{\text { deed }}=5 \times 9 \overline{\text { deed }}$ $\overline{\mathrm{abcba}}$ can be divided by 5 and 9, so the maximum value of $a$ is $5, b=9$, 45 is divisible by $59 \square 95$, then $\square=8$, the maximum five-digit number is 59895. Therefore, the answer is: 59895