The number 15 is an integer that comes after 14 and before 16. It is often associated with various concepts, such as age, where a person turns 15 during their teenage years. In sports, 15 can represent the number of players on a rugby team, highlighting teamwork and strategy. In mathematics, 15 is considered a composite number because it can be divided by 1, 3, 5, and 15. It is also the sum of the first five positive integers: 1 + 2 + 3 + 4 + 5. This makes 15 a significant number in both everyday life and mathematical contexts.