Animal Crossing: New Leaf's LTD was revealed to be 2.73 million.
Since the game is only available in Japan so far, we're able to check that number against both weekly Japanese sales trackers, Media Create and Famitsu.
Animal Crossing is available as a retail release, via a download card, or via the eShop.
Media Create is confirmed to track only the retail version of titles.
Famitsu is confirmed to track the retail and download card versions.
Animal Crossing New Leaf's LTD via Media Create (as of Dec. 30th, 2012): 1,969,955
Animal Crossing New Leaf's LTD via Famitsu (as of Dec. 30th, 2012): 2,286,977
Simple extrapolation lets us see that AC:NL has sold nearly 800k digital copies (eShop and download card combined) and nearly 500k eShop copies.
As I said in the financials thread, this is quite an incredible feat for Nintendo in regards to the eShop.
Nearly 30% of all copies sold are digital. Keep in mind that AC:NL usually skews toward a younger crowd.