The "In Days" function will take a number that is expressed in days and convert it to the number of seconds. So "In Days(1)" will be 86400 which is the number of seconds in a day.
In the table that I provided, there are three columns.
Input: this column contains the value that you provided. It is a time which is measured in days (not seconds)
In Seconds: This column contains the value that you provided, but in seconds. This column is a formula which uses the "In Days" function.
Formatted "In Seconds": This column changes the number of seconds in the "In Seconds" column and uses the format that you want "min:s". Note that this column is not really needed other than providing the 0 minutes and the colon to separate minutes from seconds. The In Seconds column shows that this is truly going to be 1.876 seconds (or 1.9 when rounded to one decimal place).
Any of the items in bold text are simply column names. You could specify anything you want there.
One last thing that may help. Since there are 86400 seconds in a day, your value of 0.000021713*86400 = 1.8760032. This shows that your 0.000021713 is really telling you the fraction of a day that was measured.
Dan Obermiller