Number Properties Tip?

[underdog]

How many different positive integers are factors of 441?

(A) 4
(B) 6
(C) 7
(D) 9
(E) 11
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i get that 441 = (9)(49) = (3^2)(7^2) easy enough. However, there has to be a shortcut for plugging in all the additional combination of integers?

[akhpad]

As you did it
441 = (9)(49) = (3^2)(7^2)

Total no of factors = (2+1)(2+1) = 9