It has also been challenging to establish the identity of our 200,000th subscriber.
Anyway, it appears number 200,000 may have been this person!
Kathryn lives in Broomall, Pennsylvania (just outside Philadelphia).
She said: "I happened to come across your channel a few days ago. I'm horrible at math, but for some reason your channel just puts me in a better mood."
When not watching Numberphile, she is into musical theatre.
Number 200k may also have been Travis from Italy.
He's 14 years old and said: "You're lucky because I'm good with English despite my young age. Even though I'm not perfect yet."
Of course Numberphile has had many more than 200,000 people subscribe in total - nearly 218,000 in fact - but sadly we have lost some of them as time goes by. But Kathryn and Travis helped take us past 200,000 current subscribers.