139 is a prime number. Factor pairs: 139 = 1 x 139. Its only factors are 1 and 39. Prime factorization: none.
How do we know that 139 is a prime number? The square root of 139 is an irrational number approximately equal to 11.79. If 139 were not a prime number, then it would be divisible by at least one prime number less than or equal to 11.79. Since 139 cannot be divided evenly by 2, 3, 5, 7, or 11, we know that 139 is a prime number.
139 is never a clue in the FIND THE FACTORS puzzles.
Excel file with puzzles and the previous week’s factor solutions: 12 Factors 2014-06-02