Depending on the pixel densities for the phones , the icon size of the app should be as follows:
Device Type - Icon Size in pixels
* ldpi - 36px x 36px
* mdpi - 48px x 48px
* hdpi - 72px x 72px
* xhdpi - 96px x 96px
The application icon is present at res/drawable-(dpi)/icon.png. The icon is placed for ldpi, mdpi, hdpi and xhdpi profile in the corresponding directories.