Is 111 Prime?

Check if 111 is a prime number. A prime number is only divisible by 1 and itself.

Is prime?
Result: ✗ NO — 111 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 111 is prime, we need to verify that no number from 2 to √111 divides it evenly.

Step 2 Determine Testing Range

Since 111 is odd, we only need to check odd divisors.


We only need to test up to √111 ≈ 10.54, which rounds down to 10.


If 111 has a factor larger than √111, it must also have a corresponding factor smaller than √111.

Step 3 Test Odd Divisors

Testing: 3, 5, 7, ... up to 10


111 ÷ 3 = 37 (no remainder!)

We found that 3 divides 111 evenly!

Step 4 Conclusion
111 = 3 × 37

Since 111 has factors other than 1 and itself, 111 is NOT a prime number.