39 is not a prime number because it has four factors: 1,3,13,39 and because prime number are numbers who has 2 factors.
a prime number is a number that can only be divided by 1and its self... 1 isnt a prime number but 2, 3, 5, 7, 9, 11 etc... are prime numbers.
Composite
There isnt
There isnt one country who invented all the numbers.
23, 37, 79 and 51 (assuming 1851 is a typo, 18 isnt a prime) if not a typo 1851 isnt a prime number anyway, it divides by 3
There isnt any
Well There Isnt Numbers..
Composite
there isnt one
13 and 3. Isnt it?
if you hav a remainder<divide that by 2, wich shud b 1/2. easy? too bad if it isnt. haha!