What if you have values in seconds and you would like to know how much time is there directly?
1. On the cell where you want to see calculated time
let's say B1, right click -> "Format Cells..." and there go to "Number" and on "Category" select "Custom" and as type select hh:mm:ss.
NOTE: my advice is to add hh (hours) too because if you have seconds more than one hour, you will see only the minutes after the hour and is wrong (e.g. 7144s = 01:59:04 for hh:mm:ss and 59:04 for mm:ss)
2. Add your seconds in another cell
Let's call it B2
3. On the cell B1, add this value
NOTE: IFERROR will show nothing if you do not have any value in B2 yet).