Croma for Android is a lovely app for managing and creating color palettes. It is available for free on the Google Play Store and offers enhanced functionality via in-app purchase.
If you've ever done design work, you know how much a good color palette can make all the difference. Croma is designed with Android's new Material Design asthetic, which makes it feel all the more fresh. As the quick walk-through video shows, creating a palette (complete with color code values) from an existing image is simple and elegant.