I'm pretty sure the answer would be 1,2,4,16 (:
Nobody invented them, they are just names for numbers. A prime number has only 2 factors which are 1 and itself. Composite numbers are everything else except 1 and 0. 1 and 0 are neither prime, nor composite.
The property of prime or composite is not defined for the number 1, just as it is not defined for any number that has a fractional part. There are no special names for numbers that are not prime nor composite.
fraction
A fraction names part of a region or part of a group. The top number of a fraction is called its numerator and the bottom part is its denominator. They are separated by a line called a "fraction bar."
1,2,3,5,6,10,15,30
1,2,3,4,6,12
I'm pretty sure the answer would be 1,2,4,16 (:
13 and 19 aren't composite. 1,2,5,10 1,13 1,2,3,6,9,18 1,19
the set of factors
As a product of its prime factors: 2*3*3*5*139 = 12510 or as 2*32*5*139 = 12510
1,3,9,27
One and the number itself.
1, 3, 9, 27
Any prime number only has two factors, one and the number itself.
1 and 71
1,2,3,4,6,9,12,18,36