PS OG 209 Factors of 441

[Uhlemann]

Q: How many different positive integers are factors of 441?

A: 4
B: 6
C: 7
D: 9
E: 11

The official answer states in the first line: Recognize that 441=(9)(49).

I know my basic factors but this seems like an extreme case. Is there a trick to solving this problem?

[muks]

441=(9)(49)=(3^2)(7^2)
No. of factors= (2+1)(2+1)=(3)(3)=9