Want to build your own URL shortener? Have a bunch of sequential ID’s but don’t want it to be obvious what the next or previous in the sequence is? Base62 might be a good fit. Instead of 10 possible characters per digit you have 62, compressing the size of your identifier. Plus with a custom alphabet order, the next number in the sequence isn’t easily apparent. I have open sourced a CFML library that allows you to convert between base 10 and 62 here: https://github.com/ryanguill/cfmlBase62 - it supports custom alphabets (will also help generate one for you) and supports integers between 0 and 263-1 (9,223,372,036,854,775,807) so it can probably handle all of the nine quintillion identifiers in your database. 

base62 = new Base62();
base62.fromBase10(123); //b9
base62.toBase10("b9"); //123

There is a complete set of tests. See here for some more example usage or here to see a custom alphabet being used. Supports Lucee 4.5+ and ACF 10+. Pull requests and issues welcome!