The function how-many-days-hours-minutes-seconds is part of the LAML time library, which we here illustrate by means of a number of examples.
(current-time)
999789132
(time-decode 1000000000)
(2001 9 9 3 46 40)
(time-decode 0)
(1970 1 1 2 0 0)
(time-interval 1000000000)
(31 8 2 5 1 46 40)
(weekday (current-time))
Thursday
(danish-week-number (current-time))
36