We often scan entire landscape of mobile apps to produce useful data for research. Based on this activity, we have an idea of how many apps are in the world. Of course the values are estimated. More details about this calculation are detailed in below table:
| Google Play (apps for mobiles and wearables) | 1.7 million |
| Apple AppStore | 1.2 million |
| Amazon AppStore (apps for Android/Kindle Fire) | 200 K |
| Microsoft Store (apps for Windows Phone) | 100 K |
| Pebble (apps for pebble watch) | 2 K |
| TOTAL | 3.2 million |
Image source: http://www.veteransenterprise.com/images/articles/advice-tips/mobile-apps.jpg