**Quote:**

1. Clean number is defined as a prime number here. Sufficient.

2. Clean number is defined as an odd number here. Sufficient.

You are right about statement 1, it defines what a clean number is. Please look carefully at statement 2 though, it doesnt define a clean number as odd, it says a clean number must be odd. That =/= clean numbers are all odd numbers.

1. A clean number is an integer divisible by only 2 factors, one of which is greater than 2.

2. A clean number must be odd.

Think of it this way:

"A clean number is an integer divisible by 4"

"A clean number must be even"

^^

The latter doesnt mean that all even numbers are clean, and we already know that all of the numbers are even thanks to statement one.