177 is a composite number.

Factor pairs: 177 = 1 x 177, 3 x 59

Factors of 177: 1, 3, 59, 177

Prime factorization: 177 = 3 x 59

Here is a magic square made entirely of prime numbers:

What number do you get when you add up the numbers of any one of its rows, columns, or diagonals?

According to Wikipedia, you can’t get a smaller magic sum than 177 when all the numbers in the magic square are prime numbers. Wolfram MathWorld has several Prime Magic Squares of various dimensions up to 13 × 13. Two of the squares include the number 1, which is not a prime number but is sometimes permitted to be in a prime magic square because it is not a composite number.

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Excel file of puzzles and previous week’s factor solutions: 12 Factors 2014-07-14