11. Given the following equation where different Chinese characters represent different digits, and the same Chinese characters represent the same digits, 业步高 $\times$ 业步高 $=$ 高升抬步高
Then, the number represented by 高升抬步高 is . $\qquad$
【Answer】 50625
【Analysis】 "Indelible two-digit tail"
$$
\begin{array}{l}
\overline{a b} \times \overline{a b} \equiv \overline{a b}(\bmod 100) \\
\overline{a b} \times \overline{a b}-\overline{a b} \equiv 0(\bmod 100) \Rightarrow 100 \mid \overline{a b} \times(\overline{a b}-1)
\end{array}
$$

Since $\overline{a b}$ and $\overline{a b}-1$ are coprime, there are four cases:
$100|\overline{a b}, 100| \overline{a b}-1,25 \mid \overline{a b}$ and $4|\overline{a b}-1,4| \overline{a b}$ and $25 \mid \overline{a b}-1$.
$\overline{a b}$ can take $00,01,25,76$.
This problem verifies the answer as $225 \times 225=50625$.