What is 21 (number)?
{{dablink|This article is about the number 21. For the year, see [[21]].}}{{Infobox number}} '''21''' ('''twenty-one''') is a [[number]]. It comes between [[twenty]] and [[twenty-two]], and is an [[odd number]]. It is divisible by [[1 (number)|1]], [[Three|3]], [[Seven|7]], and 21. Twenty-one is also a name of [[blackjack|a popular card game]] and is the age at which people in the [[United States]] can buy [[alcoholic drinks]]. In [[Roman numerals]], 21 is written as '''XXI'''. In Greek numerals 21 is written as κα {{Math-stub}} [[Category:Integers]]