200,000 of them optimised for iPad.
The figures were divulged at another triumphant product update from the Cupertino firm last night.
Apple CEO Tim Cook proclaimed that his firm has both feet planted in the post-PC future, and the wild success of its less-than-four-year-old app store is evidence that Apple is leading the charge.
Apps offer a new form of software distribution and are designed to work on phones and tablets. As such they have eclipsed the old-school CD-ROM model for shipping software to PCs.
The Apple App Store now comprises 200,000 apps for the iPad, which has only been around for two years. At the weekend, Apple confirmed lifetime downloads for the store had passed the 25 billion mark.
In all, Apple has sold 315 million iPads, iPhones, and iPod Touches, with 62 million of these iOS-powered devices being sold in Q4 2011 alone and 172 million in 2011.
Tim Cook said the 15.4 million iPads sold during the quarter beat the sales performance of nearly every other major PC manufacturer during that same time period.