That is not a number carved in stone. The way to figure it out, is to take your pulse for one full minute (to get as close as possible), and multiply that by 60. That is how many are in an hour....
The average adult heart beats 60-100 times per minute. 60 to 100 beats/min * 60 min/hour * 24 hours/day = beats/day. You can do the math.
7500-9000 kilojoules per day
23.5
86,400 seconds.