Okay, you can do this the easy way:
or the complicated way (LOL, I typed up the stuff below before I found the above app

):
Here's how to get the exact installation date/time:
- find the name of the app's package if you don't already know it
- one way is viewing the
Play Store (
https://play.google.com) and finding and focusing on the app you've previously installed
- the package name will appear at the end of the app's URL (web link) after the "?id=" portion
- for example, for my "
RAM Truth" app, it's full URL is
and so the package name is "
sa.ramtruth"
- from a shell prompt (either an
adb shell or a
Terminal Emulator for Android session), type the following command:
pm dump <packagename> | grep -i -e "firstInstallTime"
and replace <packagename> with your app's specific package name
- for example, doing this for my
RAM Truth app:
D:\>adb shell
angler:/ $ pm dump sa.ramtruth | grep -i -e "firstInstallTime"
firstInstallTime=2016-12-29 19:45:04
angler:/ $
Cheers!