How can I check if my android phone has been hacked?

What made you think it was? Pop-ups everywhere and a battery that drains for no reason are usually just a dodgy app, not someone actually in the phone. Places to look: - Settings > Accessibility, any app there you don't recognise is a red flag, that permission lets it read the screen - Device admin apps (search "device admin" in Settings) - the app list for anything you didn't install, sort by recently installed - Play Store > profile > Play Protect > Scan - your Google account's security page and the list of signed-in devices If you find something, uninstall it, change your Google password from another device and turn on 2-step verification. Still weird after that, back up and factory reset.