To round a number to the nearest whole number, you have to look at the first digit after the decimal point. If this digit is less than 5 (1, 2, 3, 4) we don't have to do anything, but if the digit is 5 or greater (5, 6, 7, 8, 9) we must round up.
Considering the given number:
The first digit after the decimal point is 8
Since the is greater we round up
Hence
Therefore, 5834.805 to the nearest whole number is 5834