### 149 and Level 2

149 is a prime number. Factor pairs: 149 = 1 x 149. Its only factors are 1 and 149. Prime factorization: none.

**How do we know that 149 is a prime number?** The square root of 149 is an irrational number approximately equal to 12.21. If 149 were not a prime number, then it would be divisible by at least one prime number less than or equal to 12.21. Since 149 cannot be divided evenly by 2, 3, 5, 7, or 11, we know that 149 is a prime number.

Excel file of puzzles and previous week’s factor solutions: 12 Factors 2014-06-16

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