The integer whose value is nearest to 16.66 is 17.
To the nearest integer, 17
Since 17 is an integer, it is already rounded to the nearest fractional part.
To the nearest integer, 17
4.123105626 rounds down to 4
-39, itself, is the nearest integer.
The nearest integer to 13.5 is 14.
It could be estimated to 17 but for multiplication or division, 100/6 (= 16.66...) would be better.
12 + 0.25 + 4.75 = 17. That would be rounded to 17 to the nearest integer, 20 to the nearest ten, and 0 to the nearest hundred, thousand, (and higher powers of 10).
It is not an integer, nor can it ever be an integer. It can, however, be rounded to the nearest integer, in which case 0.1 will round to 0 to the nearest integer.
2,138.5 rounded to the nearest integer is 2,139
It is already rounded to the nearest integer.