As I understand it Islamic law forbids any man of having more than four wives. Ibn Saud apparently had 22 wives. How was he able to reconcile this with Islam, especially considering the highly religious nature of the Saudi state?
I don't think he ever had more than four at once.
Robert Lacey's "The Kingdom" describes King Abdulaziz repeatedly divorcing women so that he can keep to the Islamic limit of four wives. He even remarried one of them, Hassa Al Sudairi (mother to the current Saudi king Salman and the late King Fahd), after he regretted divorcing her.