It says Cambodia has 74 characters, "the most of any language in the world". That sounds wrong. Hindi's Devanagari has 100+ characters, though some are certainly related to each other.
26 to 74 is just double, and most likely some are more common in written communication than others.
It's closer to triple, isn't it?
It depends on how you define "character", I guess. The hirigana or katakana "alphabets" have 48 characters. These alphabets map best to the western use of characters.
Kanji is probably what you are thinking of, where each word in Japanese gets its own "character". There are ~50,000 different kanji symbols.