Or anything else that goes in an address book entry associated with your phone number.
Like your full name, job title, employer, email address, physical address, date of birth, social media profiles, family relations... the list goes on.
All of that associated information is often stored alongside your phone number. If one person you know does that, and also uses a facebook property and shares their address book through that (e.g. whatsapp), facebook has all that information about you.
If you're curious, check the list of additional fields you can add to a contact in your address book for how much Facebook could get about you