No. 15 is the product of two prime numbers: 3 and 5
Since there are infinitely many primes, there are infinitely many numbers that are products of 3 primes.
30, 42, 66, 70, 78
The product of negative number and a positive number is always a negative. The product of two positive numbers, or two negative numbers, is always a positive.
If the signs of both numbers are the same, the product will be positive. If the signs of the numbers are different, the product will be negative.
Food doesn't exactly have model numbers but the food has a number to identify what product it is.
A prime number is a positive integer that has exactly two different factors: 1 and itself. This is why 1 is not a prime number: it has the factors 1 and itself, but they are the same - it does not have exactly two different factors.
A composite number is the product of two or more prime numbers. A prime number has exactly two factors, 1 and the number itself; a composite number has at least one more factor than the two that a prime number has.
If all three numbers are positive then the product obviously has to be positive. If TWO of the three numbers are negative, then the product is also positive. But if exactly ONE of the three numbers is negative or if all THREE are negative, then the product must be negative. In general, a product of numbers is negative if an ODD NUMBER of the terms is negative.
There are an infinite number of integers with "only 7 factors". Any number which is the product of exactly 7 prime numbers.
If two numbers have different signs, then their product is negative. If two numbers have the same sign, then their product is positive.
The largest integer that is not the product of two or more different primes would be the largest prime number. Because there are an infinite number of prime numbers, there is no largest integer that is not the product of two or more different primes.
Such a number would either have to be a perfect cube of a prime number, such as 33 = 27 (the only one in the specified range), or the product of exactly two different prime factors, such as 2 x 3, 2 x 5, 3 x 31, etc.
Any number of the form a*b^4 where a and b are different prime numbers, or c^9 where c is a prime, will have exactly 10 factors.
A prime number has exactly two factors, 1 and the number itself. 1 is not a prime number, and the product will be a composite number if any other prime is used as a factor and multiplied by another prime.
Any prime number to the power 12...or 10, if you allow 1 and the number itself. There are probably others, but those are the most obvious ones. So 2^12=4096 would probably be the smallest. Also try the product of any 11 different prime numbers, Or, say, 1,2,4,8 and seven different prime numbers etc.
2 x 3 x 5 = 30