Turning $2 into $20,000 has never been easier—if you're lucky.

Some uncirculated U.S. $2 bills may be worth up to $20,000, but it depends on a few factors, according to Heritage Auctions, one of the largest auction houses in the world

"Americans don't spend $2 bills because they think they are markedly scarce. However, the numbers tell us a different story," Dustin Johnston, vice president of Heritage Auctions, told MarketWatch

Just in the last five years, they've printed 100 million $2 bills. The fact that they don't circulate and are kept as mementos is a little bit odd. Very few of them have numismatic or collector value

So what sets apart the $2 bills that may have significant value? It all comes down to three key factors: the serial numbers

The serial number is the big one. It's printed on the left and right sides of the front of the bill

"A serial number '1' for a 1976 $2 bill would be worth $20,000 or more. But a majority of those people holding 1976 $2 bills are only worth face value

Other high-value serial numbers include what collectors call "solid" or "ladders". Solid serial numbers are codes that are all the same digit

like 88888888888, while a ladder number features digits listed in ascending order, such as 12345678910.