The number forty is an integer that follows thirty-nine and precedes forty-one. It is often represented in Roman numerals as XL. In various cultures, forty can symbolize a significant period, such as the forty days and nights of rain in the biblical story of Noah's Ark. In mathematics, forty is an even number and can be divided by 1, 2, 4, 5, 8, 10, 20, and 40. It is also the product of 8 and 5. In terms of age, reaching forty is often considered a milestone in many societies, marking the transition into middle age.