√21 = 4.582575695. 21 is not a perfect square; the result is irrational.

Is 21 a perfect square?

No, 21 is not a perfect square. Its square root is irrational.

What is 4.582575695 squared?

4.582575695 squared is approximately 21. (4.582575695)² ≈ 21

Instant answer with step-by-step solution

√21 = 4.582575695

√21 = 4.582575695

⚠ 21 is not a perfect square — result rounded to 10 significant figures

We need to find √21 — a number that when multiplied by itself equals 21.
21 is not a perfect square. Its square root is irrational.
It falls between √16 = 4 and √25 = 5.
Using the formula √N = N^(1/2): √21 = 21^0.5 = 4.582575695
Verification: 4.582575695 × 4.582575695 ≈ 21 ✓ (rounded to 10 significant figures)

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