1 Drop it into Truecaller — name, photo and crowd-sourced spam tags often resolve instantly.
2 Reverse-lookup the number in quotes on Google plus on thatsthem.com, truepeoplesearch.com, nuwber.com and fastpeoplesearch.com.
3 Run it through epieos.com — pulls linked Google account, name and avatar.
4 Save the number as a contact, then open WhatsApp, Telegram and Viber. The profile photo, display name and "last seen" leak without any message being sent.
5 On Telegram, search the number in the "New Message > Contacts" field — many accounts are number-discoverable.
Free carrier/line-type lookup (carrierlookup, numverify) confirms country, carrier and mobile vs VoIP.
6 Hit "forgot password" on Facebook and Instagram with the number — the masked recovery email is shown to you for free.
7 Area code gives registration region only. For live location you need the target to install Life360, Find My or share a live pin