This is not the case in the U.S. (discussed elsewhere in this discussion). All phone numbers, landline or mobile, have an area code associated with a specific city/region. Since number portability became a thing in the early 2000s it’s much more common for cell phone users to just keep their number from decades ago, however, which will often not match the physical area they now live in.
The US is also somewhat unique (not the only country, but one of a few) in that we can port numbers between landline and mobile. Most places keep them separate.
I used this feature recently, after my mom passed. She had the same home number we grew up with, for fifty years. I ported it over as a second line on my mobile. Partly nostalgia (okay, mostly), partly because it was a pretty great number for memorization; it has an excellent number pattern.
