This is the 5329th most frequent Chinese word.
二十一
Twenty-one.
The word '二十一' is used to denote the numeral twenty-one, specifically representing age in this context.
我现在二十一岁。
I am currently twenty-one years old.
Here, '二十一' indicates the solution to a problem, used as a numerical response.
这道题的答案是二十一。
The answer to this question is twenty-one.
In this scenario, '二十一' specifies the count of students, applying numerical counting.