Seconds to Days
According to Wikipedia:
The second (symbol: s, also abbreviated: sec) is the unit of time in the International System of Units (SI), historically defined as 1⁄86400 of a day – this factor is derived from the division of the day first into 24 hours, then to 60 minutes and finally to 60 seconds each (24 × 60 × 60 = 86400).
Analog clocks and watches often have sixty tick marks on their faces, representing seconds (and minutes), and a “second hand” to mark the passage of time in seconds. Digital clocks and watches often have a two-digit seconds counter.
SI prefixes are frequently combined with the word second to denote subdivisions of the second: milliseconds (thousandths), microseconds (millionths), nanoseconds (billionths), and sometimes smaller units of a second.
Multiples of seconds are usually counted in hours and minutes.
Though SI prefixes may also be used to form multiples of the second such as kiloseconds (thousands of seconds), such units are rarely used in practice.
An everyday experience with small fractions of a second is a 1-gigahertz microprocessor which has a cycle time of 1 nanosecond.
Camera shutter speeds are often expressed in fractions of a second, such as 1⁄30 second or 1⁄1000 second.
How to calculate the number of days from seconds?
One day has 24 hours. 1 hour has 60 minutes. 1 minute has 60 seconds.
Thus, the total number of seconds in a day = 24 x 60 x 60 = 86400 seconds.
If 86400 seconds = 1 day
1 second = 1⁄86400 days
N seconds = (1⁄86400) x N days
With this formula,
10,000 seconds = (1⁄86400) x 10,000 = 0.115740740740740 days.
In simple words,
Divide the number of seconds by 86400 to get the number of days.