To check
It is NOT an even number , so will not divide by '2'
It does NOT end in '5' , so will not divide by '5'.
The digits 381 do not sum to '9' ( 3+ 8 + 1= 12 = 3) So does not divide by '9'. 4. The clue is that the digits sum to '3' . Three is a Prime number , so it might divide by '3'. If so, then it is a composite number.
Hence
3)381 = 127 : No remainder.
So 127 X 3 = 381 / Hence it is a composite number.
NB When testing for composition of numbers, the other prime number to try is '7'.
4, composite. 67, prime.
Prime
1 is special 2 prime 3 prime 4 composite 5 prime 6 composite 7 prime 8 composite 9 composite 10 composite 11 prime 12 composite ext.
5 prime, 25 composite.
Composite
All composite.
381 = 3 × 127
Presumably 2 composite integers
neither prime or composite
It is prime
It would be impossible to list them all, since numbers go on forever, but here are some of them: 2 - Prime 3 - Prime 4 - Composite 5 - Prime 6 - Composite 7 - Prime 8 - Composite 9 - Composite 10 - Composite 11 - Prime 12 - Composite 13 - Prime 14 - Composite 15 - Composite 16 - Composite 17 - Prime 18 - Composite 19 - Prime 20 - Composite 21 - Composite 22 - Composite 23 - Prime 24 - Composite 25 - Composite 26 - Composite 27 - Composite 28 - Composite 29 - Prime 30 - Composite 31 - Prime 32 - Composite 33 - Composite 34 - Composite 35 - Composite 36 - Composite 37 - Prime 38 - Composite 39 - Composite 40 - Composite 41 - Prime 42 - Composite 43 - Prime 44 - Composite 45 - Composite 46 - Composite 47 - Prime 48 - Composite 49 - Composite 50 - Composite
No, 381 is not a prime number. Other than itself and 1, it is divisible by 3 and 127.
4, composite. 67, prime.
Prime
1 is special 2 prime 3 prime 4 composite 5 prime 6 composite 7 prime 8 composite 9 composite 10 composite 11 prime 12 composite ext.
5 prime, 25 composite.
Prime.