Alphabetical Order Puzzle - Solution

The Puzzle:

Alphabetical Order
Find a number with its letters in alphabetical order.

Example: "five" has "fiv" in alphabetical order, but not "e".

Our Solution:

Forty

It is the only number we know of in English with its letters in alphabetical order. And that is the correct spelling.

Examples from other languages:
In Spanish there is Dos (2)
In French there is Deux (2), Cinq (5), Dix (10), Cent (100)
In German there is Eins (1)
See this puzzle without solution