No. A number that ends in 5 is divisible by 5, so it can't be prime unless it is 5 itself. Also, 7+6+5 = 18. Since 18 is divisible by 3 and by 9, 765 is also divisible by 3 and 9. It is easily seen that 765 factorises to 3 x 3 x 5 x17.
1,3,5,9,15,17,45,51,85,153,255,765
9 divided by 765 is ~0.0117647058824
Yes. 3,060 divided by 4 is 765.
1, 3, 5, 9, 15, 17, 25, 45, 51, 75, 85, 153, 225, 255, 425, 765, 1275, 3825
No. A number that ends in 5 is divisible by 5, so it can't be prime unless it is 5 itself. Also, 7+6+5 = 18. Since 18 is divisible by 3 and by 9, 765 is also divisible by 3 and 9. It is easily seen that 765 factorises to 3 x 3 x 5 x17.
No.
1,3,5,9,15,17,45,51,85,153,255,765
yes
85
Composite. Is divisible by 5
9 divided by 765 is ~0.0117647058824
Yes. 3,060 divided by 4 is 765.
The numbers that are divisible by 255 are infinite. They include: 255, 510, 765, 1020, 1275, 1530, 1785 . . .
Composite, since it is divisible by 5. ■
Yes, you get a quotient of 255 which is a whole number and with no remainders.
765 ÷ 9 = 85