User blog comment:Grizzly Bear/Numbers- Words, Not Numbers/@comment-25220801-20141204090121

I think as well as dates, percentages are okay in numeric form as well. It's an odd thing to predict, but I guess it's down to how we perceive numbers when reading. We quickly absorb the meaning of dates and percentages so it doesn't jar us out of the narrative, the same with using '24/7' or odds like '8 to 1'.

Also, in a specific creepypasta sense, I think you can get away with using '666' (otherwise even the most short sighted parent would've noticed 'six hundred and sixty six' on their child's head and raised a concerned eyebrow). ;)