1. The problem is to understand the number 15. 2. 15 is a positive integer, a whole number greater than zero. 3. It is an odd number because it is not divisible by 2. 4. 15 can be factored into prime factors as $$15 = 3 \times 5$$. 5. This means 15 is a composite number with prime factors 3 and 5. 6. In summary, 15 is an odd composite number with prime factors 3 and 5.