WTW that's like decimal, hexadecimal, but it's 65536? I am writing a program to write and parse a text file. This text file must be openable in Notepad, and must have fixed-character-width numbers for a small portion of the information some of the files will contain. (The rest will be human readable.)

If I use the Unicode Private Use Areas, I can reliably achieve 2^16: base-65536 (if my numbers are fixed to two characters' width, two characters can reach 4,294,967,296). But what can I call this?

Yes, I know what I'm doing, and no, I am not trying to reduce my filesize by doing this.