365 (number)

365 (three hundred [and] sixty-five) is the natural number following 364 and preceding 366.

Mathematics

365 is a semiprime centered square number. It is also the fifth 38-gonal number.

For multiplication, it is calculated as ${\displaystyle 5\times 73}$. Both 5 and 73 are prime numbers.

It is the smallest number that has more than one expression as a sum of consecutive square numbers:

${\displaystyle 365=13^{2} 14^{2}}$

${\displaystyle 365=10^{2} 11^{2} 12^{2}}$

There are no known primes with period 365, while at least one prime with each of the periods 1 to 364 is known.

Timekeeping

There are 365.2422 solar days in the mean tropical year. Several solar calendars have a year containing 365 days. Related to this, in Ontario, the driver's license learner's permit used to be called "365" because it was valid for only 366 days. Financial and scientific calculations often use a 365-day calendar to simplify daily rates.

References