Square Root Calculator › Square root of 21
Square Root of 21
√21 ≈ 4.582576
21 is not a perfect square, so √21 is an irrational number that is approximately 4.582576. In simplified radical form, √21 = √21.
√21 lies between √16 = 4 and √25 = 5.
| Number | 21 |
| Square root (decimal) | 4.582576 |
| Simplified radical | √21 |
| Perfect square? | No |
| Rational? | No |
Calculate another square root
Nearby square roots
Frequently asked questions
Is 21 a perfect square?
No, 21 is not a perfect square, so its square root is irrational and approximately 4.582576.
What is the square root of 21 in simplest radical form?
√21 = √21 in simplest radical form.