AI overview
21 is a whole number that comes after 20 and before 22 in the sequence of counting numbers. It is the product of multiplying 3 by 7, making it a composite number with practical applications in mathematics and everyday contexts like telling time and measuring.
AI-generated from the Wikipedia summary — may contain errors.
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← 20 21 22 23 24 25 26 27 28 29 → List of numbers Integers
← 0 10 20 30 40 50 60 70 80 90 →