Is 28851 a prime number?

Answer 1

It is divisible by 3:

10 Mod 3 = 1 ------>

10^n Mod 3 = 1^n = 1 ------>

Sum over cn 10^n Mod 3 =

Sum over cn Mod 3

28851 Mod 3 = (2 + 8 + 8 + 5 + 1) Mod 3

= 0

Answer 2

http://primes.utm.edu/lists/small/1000.txt

Answer 3

nope, it is divisible by 3