Azkar: Athan Prayer is a comprehensive Islamic reference app that includes all the necessary features for Muslims worldwide. Developed by Hamza Oqbah, the app is available for free on the iPhone platform. The app is easy to use and offers a smooth experience for users.

One of the most impressive features of the app is that it includes all the Azkar and Duas with Prayer times, the Qibla, and the Noble Qur’an with full interpretation and translations. It's also impressive that the app does not require an internet connection. Users can hear the Azkar by voice and play audio in the background. The app also allows users to read the Athkar very nicely. Moreover, users can create their own Azkar and synchronize them easily. The app also has a Tasbih counter, Fasting Tracker, and a biography of the Prophet.

Overall, Azkar: Athan Prayer is an excellent app that offers a comprehensive reference for Muslims. The app is user-friendly, and it's easy to navigate. It's a great tool for anyone who wants to keep up with their daily prayers and spiritual practices.