Нашёл 11 млн ответов for 'Mobile number'.
https://yotracker.com/
https://en.wikipedia.org/wiki/Telephone_number
https://en.wikipedia.org/wiki/Telephone_numbers_in_Russia
https://en.wikipedia.org/wiki/List_of_mobile_telephone_prefixes_by_country
https://findmykids.org/blog/en/free-mobile-number-tracker
https://mobilenumbertracker.com/
https://www.phone-location.info/Phone-Number-Lookup
https://www.phone-location.info/mobile-number-locator
https://www.phone-location.info/find-my-android
https://zadarma.com/en/tariffs/numbers/united-states/mobile/