I don't think you can know because every generation matters. It's not just how prolific he was, but how prolific his sons were compared to others in their generation, on to grandsons and so on. If being a descendant of Khan was prestigious, then the descendants could increase exponentially down the line.
There are plenty of places traveling in Muslim South Asia where it seems every fukking person's last name is Khan. And it is THE main highest status name too, to this day.
Even in Bollywood, the three biggest actors over the last 25 years are all Khans. And they're not even related.
