What is 31 (number)?
{{dablink|This article is about the number 31. For the year, see [[31]].}} {{Infobox number | number = 31 }} '''31''' ('''thirty-one''') is a [[number]]. It comes between [[thirty]] and [[thirty-two]], and is an [[odd number]]. It is also the 11th [[prime number]], after 2, [[Three|3]], [[Five|5]], [[Seven|7]], [[Eleven|11]], [[Thirteen|13]], [[Seventeen|17]], [[Nineteen|19]], [[Twenty-three|23]], and [[Twenty-nine|29]]. The factors of thirty-one are 1 and 31. {{Math-stub}} In Roman Numerals, 31 is written as '''XXXI'''. [[Category:Integers]] [[Category:Prime numbers]]