21 is a factor of the number because both 3 and 7 are prime factors.
Step-by-step explanation:
3^2 × 5^3 × 7
= 3 × 3 × 5 × 5 × 5 × 7
Here the prime factors are 3, 5, and 7.
Now, I've done this question before, so I'm assuming one of your options is "21 is a factor of the number because both 3 and 7 are prime factors", if this is one of your choices then choose this. It is the correct answer.
