I want to know the answer to the following question:
How many million square miles was the Umayyad caliphate at its largest size?
All the background I'm provided with is that "At its greatest extent, the Umayyad Caliphate covered 15 million km2 (5.79 million square miles), making it the largest empire (in terms of area - not in terms of population)". Is that enough to answer the question?