Square root of 21
The square root of 21 is 4.582576 (rounded to 6 decimal places). It cannot be simplified.
Square root of 21
Pick any whole number from 1 to 10,000.
How to work it out
- 1
The square root of 21 is the number that multiplied by itself gives 21.
- 2
21 is between the perfect squares 4² = 16 and 5² = 25, so its square root is between 4 and 5.
- 3
21 has no square factor bigger than 1, so the radical stays as it is.
- 4
A calculator, or long division of digits, gives
LaTeX source of the formulas on this page
\[ \sqrt{21} = \sqrt{21} \approx 4.582576 \]
\[ \sqrt{21} \]
\[ \sqrt{21} \approx 4.582576 \]Squares around 21
| Number | Squared |
|---|---|
| 3 | 9 |
| 4 | 16 |
| 5 | 25 |
| 6 | 36 |
Questions
What is the square root of 21?
The square root of 21 is 4.582576 (rounded to 6 decimal places). It cannot be simplified.
Is 21 a perfect square?
No. It lies between 4² = 16 and 5² = 25.
What is 21 squared?
21 × 21 = 441.
What is the square root of 21 rounded to 2 decimals?
4.58.