Is 25 Prime?

Check if 25 is a prime number. A prime number is only divisible by 1 and itself.

Result: ✗ NO — 25 is NOT a prime number

Step-by-Step Solution

Step 1 What is a Prime Number?

A prime number is a natural number greater than 1 that has exactly two factors: 1 and itself.

To check if 25 is prime, we need to verify that no number from 2 to √25 divides it evenly.

Step 2 Determine Testing Range

Since 25 is odd, we only need to check odd divisors.

We only need to test up to √25 ≈ 5.00, which rounds down to 5.

If 25 has a factor larger than √25, it must also have a corresponding factor smaller than √25.

Step 3 Test Odd Divisors

Testing: 3, 5, 7, ... up to 5

25 ÷ 3 = 8 remainder 1

25 ÷ 5 = 5 (no remainder!)

We found that 5 divides 25 evenly!

Step 4 Conclusion

25 = 5 × 5

Since 25 has factors other than 1 and itself, 25 is NOT a prime number.