Two numerals: “six” and “hundred,” part 2: “hundred”
Like the history of some other words denoting numbers, the history of hundred is full of sticks and stones. To begin with, we notice that hundred, like dozen, thousand, million, and billion, is a noun rather than a numeral and requires an article (compare six people versus a hundred people); it also has a regular plural (a numeral, to have the plural form, has to be turned into a noun, or substantivized, as in twos and threes, at sixes and sevens, on all fours, and the like).