400
Yes, 405 is divisible by 2 but the result 202.5 is not a whole number.
It is: 410
It is: 410
To the nearest ten, 410 To the nearest hundred, 400
400
400
Try dividing on a calculator, for example, 405 / 2, 405 / 3, etc. If you get a whole number (no digits after the decimal point), it's divisible. Otherwise it isn't.
40500
It is: 405/5 = 81
405 is a composite number because it has more than 2 factors
All multiples of 405, which is an infinite number.