It is not uncommon to see numbers written on notes. My assumption has been that a store clerk will gather all of the bills of a particular denomination from the cash drawer, count them, secure the stack with an elastic band and write the total number of notes on the top note of the stack. Then on the bank deposit form will write {# of notes} x {denomination} = $....
What caught my eye today was a 1935 $25 note in the Torex auction that has the number "36" written on it.
It is possible that some retailer at some point in time had a stack of 36 1935 $25 bills in his grubby paws??? Is there another explanation why this number would be inscribed on a $25 bill??
I once saw a 1935 $50 bill (English text) with the number "6" written on it. That didn't phase me.... I could imagine that sometime in 1945 a retailer could have had 5 1937 $50's and one 1935 $50, and the latter being on top of the stack got writ upon....
But tonight I'm going to dream about a stack of 36 $25 bills..... english, english, english, french, english, french.... etc ahhhhhh.
BTW 36 / 1840 known notes = ~ 2%