Norham castle
Begins with N and it’s on the Scottish border
Indonesia is the 1st with 231 millionCompletely off the top of my head so not thought through in the slightest.
Indonesia
Algeria
Saudi Arabia
Interesting question
Edit- Pakistan bound to be in there
Pakistan is 2nd 202 million Iran and bangladesh not in top 3Pakistan
Iran
Bangladesh
3rd probably a heavily populated country that isn't Muslim as most big Islamic populations named. China?
Egypt for 3rd?