What are the opposite words for 15?

The word "15" is a numeric term that represents the quantity of fifteen. It is not an adjective, hence it does not have antonyms in the traditional sense. However, we can look at it from different perspectives to find terms that are opposite in meaning or effect. For instance, in music, the term 15 could be antonymous with the term sixteenth. 15 could also be a synonym for a decade or fifteen years, and its antonym in this context would be single year. Additionally, in terms of mathematical operation, the antonyms of 15 could be subtraction and division.