16,000 is *probably* an embellishment.
After all, i'll be generous and say let's assume he bangs 1-2 different ladies *every* 24 hours. Any day that he doesn't bang at least one, he has to make up for it in the next 24 hour period.
16000 / 365 = 43.8356, or 44 years
half that for 2/day:
43.8356 / 2 = 21.918, or 22 years.
So anywhere between 22-44 years to visit everyone in the harem with no skipped days.
Now, let's also be generous and assume he was able to assemble the harem and start this process at 20. Two a day for a 20yo? Sure.
But 22 years later puts him at 42yo. Two a day, every day? Never a day of pushing rope because you just needed a day off to recharge your batteries?
Remember, this would have been long before dick pills, so all that banging had to just be under his own steam power!
So at some point, only one a day will be more feasible, so that could push it out as far as 64yo.
[TL;DR: It was probably more likely that guy had a heart attack before he could bang every lady in a harem of 16,000!
Hell, he might have had the heart attack *because* he tried to bang them all!
]