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.
Composite
Composite
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.
no, 5 isnt divisable by 19. 19 is a prime number and isnt divisable by anything.
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.
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
The first prime after 20 is 23.
A prime number can be less than 20, but it is not a requirement that the number has to be under 20 to be considered prime. Here is a list of all the prime numbers under 20: 2, 3, 5, 7, 11, 13, 17, and 19 .
nine (though sometimes 2 isnt counted 1,2,3,5,7,11,13,17,19
what number is not a prime factor
5 is the greatest prime factor of 20.
20 is not a prime number because 5 and 4 10 and 2 can also go into 20 not just 20 and 1