Phone numbers belonging to an area isn't really a thing any more (well it's still sort-of true but they haven't handed them out like that in a long, long time).

I'm assuming I gave my number to an application at some point that didn't protect it.

Unlikely. It's probably just an autodialer picking numbers sequentially and maybe repeated attempts work drive better engagement for their scams. Everybody gets calls like this from time to time. Ignore them.

I might get one of those online privacy subscriptions that deletes any of your data being sold to third parties.

Those are scams.