Find the n

Find the least positive integer $n$ satisfying the following conditions:

• $n^2=\overline{a_1a_2\cdots a_m}$
• $k^2=\overline{a_1a_2\cdots a_{m-1}0a_m}$
• $n \geq 4$
• $k$ is a positive integer

For example if $4^2=16$ is a perfect square then $106$ should also be a perfect square