1. Below is the inscription by the famous Chinese mathematician, Academician Wang Yuan:
数棈妻好

If different Chinese characters represent different digits from $0 \sim 9$, and assuming “数学竞赛好” represents the largest five-digit number that is a perfect square, formed by different digits. Then this five-digit number is $\qquad$
Notice that, $300^{2}=90000,310^{2}=96100$,
$$
320^{2}=102400>100000 \text {. }
$$

Thus, this five-digit number with distinct digits might be among the nine square numbers between $310^{2} \sim$ $320^{2}$.
$$
\begin{array}{l}
\text { Also, } 311^{2}=96721,312^{2}=97344,313^{2}=97969, \\
314^{2}=98596,315^{2}=99225,316^{2}=99856, \\
317^{2}=100489>100000,
\end{array}
$$

Therefore, the largest square number among the five-digit numbers with distinct digits is 96721.