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.