I have been trying several times to install Hearthstone via Amazon app store on stock Samsung Note 4, but they all failed with error message:"There was an error while installing Hearthstone: Heroes of Warcraft. Please try again." So there isn't any useful information there.
The reason I want to install via Amazon is that I want to buy packs at a discount. More information on this can be found in these links http://www.amazon.com/b?node=10558189011 and http://www.trumpfans.com/how-to-purchase-hearthstone-packs-at-a-discount-through-amazon/.
The Note 4 is the only android device I have. It is from Verizon and I don't have root access.
Best Answer
There is still currently an issue with Android, the Authenticator, Amazon Appstore, and Hearthstone. Blizzard attempted to fix it but some users are still having an issue.
Blue post: http://us.battle.net/hearthstone/en/forum/topic/16860656703?page=3#44
I also unlinked my authenticator, uninstalled the app, installed Hearthstone through Amazon Appstore, then reinstalled authenticator, and finally linked authenticator to account again. Annoying but works.