As computers have become more common worldwide the limitations of ASCII character representation have become apparent. Specifically there is no way to represent non-English language characters and no space in the 7 bits allocated to add them.
To address this problem a new standard for character representations was developed. To quote from the Unicode consortium
Unicode provides a unique number for every character,
no matter what the platform,
no matter what the program,
no matter what the language.
Commonly, Unicode uses 16 bits to encode characters allowing 216 or 65536 possible characters. These are divided into code pages specific to each language including Arabic, Cyrillic, Greek, Hebrew and Thai.
The basic Latin characters (on which English is based) are here (PDF file). Looking at this we can see that the character "2" is represented by the number U+0032.
Note the use of U+ to show that the number represents a Unicode character.
Next: Unicode SAQs