Egyptian kings 521 years listed fits squarely inside the 521 years of Bible chronology as one may now witness.

Discover the Exodus pharoah. The pharoah who reigned when Joshua destroyed Jericho. The pharoah who reigned when Chushan-Rishathaim (Judges 3:8) oppressed Israel. The pharoah who was in power after Deborah and Barack brought down Jabin the Amorite/Canaanite. There is a lot of interesting ancient history to be discovered here in these 521 years. There is also some Mitanni, Hittite and Assyrian history linked in those 521 years.