The least number that is to be subtracted from 5629 to make the result a perfect square is

Let us find the nearest perfect square below 5629 by testing close integers:
$$70^2=4900$$

$$75^2=5625$$

$$76^2=5776$$

The closest perfect square less than 5629 is $5625$, which is the square of $75$.
The least number to be subtracted is calculated as:

$$\text{Remainder}=5629-5625=4$$