How large picture can be printed of better quality if clicked through samsung s8

I want to take out the print of the photo of size 21.5 × 14.5...is it possible to do so with good quality

Some of the answer will depend on how far away you want to stand when viewing the print.
If you are looking to be within arms reach, you are probably looking for a pixels-per-inch (PPI) of 220-300 assuming the image has lots of detail to start with.

Sometimes you can get good results all the way down to 150 PPI, depending on the image and the post processing.

(You will need to look up the pixel dimensions on your image and do the math.)