File:Squaring_the_Square_(minimum).png · Wikimedia Commons · See Wikimedia Commons
Also known as the number 21, 1*21, 21*1, twenty-one, twenty one, ㉑
natural number
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.
Wikidata facts
- Instance of
- harshad number
- Followed by
- 22
- Follows
- 20
- Image
- Zlin skyscraper 01.jpg
Show 10 more facts
- code
- 30
- Unicode character
- ㉑
- number of decimal digits
- 2
- Commons category
- 21 (number)
- numeric value
- 21
- prime factor
- 7
- different from
- 21
- P8168
- dual wield
- name in hiero markup
- V20-V20-Z1
- maintained by WikiProject
- WikiProject Mathematics
via Wikidata · CC0
~6 min read
Encyclopedic overview
← 20 21 22 23 24 25 26 27 28 29 → List of numbers Integers
← 0 10 20 30 40 50 60 70 80 90 →
Excerpted from Wikipedia’s “21” article, available under the CC BY-SA 4.0 licence.
Gallery (3)
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