# Math

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Is 28851 a prime number?

• Math -

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

• Math -

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

• Math -

nope, it is divisible by 3

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