5. (10 points) The sum of the four-digit number $\overline{\mathrm{abcd}}$ and $\overline{c d a b}$ is 3333, and their difference is 693. What is the four-digit number $\overline{a b c d}$?

保留源文本的换行和格式，直接输出翻译结果如下：

5. (10 points) The four-digit number $\overline{\mathrm{abcd}}$ and $\overline{c d a b}$ sum to 3333, and their difference is 693, then the four-digit number $\overline{a b c d}$ is
2013
【Analysis】For the four-digit number $\overline{\mathrm{abcd}}$ and $\overline{\mathrm{cdab}}$, their sum is 3333, and their difference is 693. It is known that the sum 3333 is 693 less than twice the four-digit number $\overline{\mathrm{abcd}}$. Dividing $3333+693$ by 2 will give the value of the four-digit number $\overline{\mathrm{abcd}}$.
【Solution】Solution: $(3333+693) \div 2$
$$
\begin{array}{l}
=4026 \div 2 \\
=2013,
\end{array}
$$

Therefore, the answer is: 2013.