I will be checking the serial number of all my money from now on because of this:
Low serial numbers, from 00000001 to 00000100, are sought after, as well as palindromes (23599532), solids (with a digit that repeats eight times), seven-of-a-kinds (66666665), ladders (45678901) and important dates (12071941). The criteria get even more obscure from there: Undis is seeking a pi note, with the number 31415927. But the more apparently jumbled the digits, the less likely it is that anyone with the bill in their wallet will ever notice.
Which is too bad when you consider how much these fancy numbers can sell for—quite a bit more than the bill’s face value, in some cases. Right now, on Undis’ website, you can buy a $1 bill with the serial number 00000002 for a whopping $2,500. If that sounds like chump change, consider that a $5 bill with the number 33333333 goes for $13,000.