I know nothing of paper money but heard something about serial numbers and how some were valued if interesting I wondered if 21666194 interested anybody
It may interest a collector of 666, but it happens more often than you may think. To me it's a spender.
I think it would happen once in every thousand (at the end of the serial), plus more times for positions elsewhere in the serial. (It's also interesting that I'm replying to post 2725665. Across The Street From The Beast?)