How many days were in the year 46 BC?

We're talking here about the longest recorded year in human history, aptly named the "Year of Confusion." There were a total of 445 days.

The year marked the transition from the Roman calendar to the Julian one. Every few years, the Romans were in the habit of adding leap months to keep the calendar in synch with the solar year. Civil wars played havoc with this scheme

Julius Caesar added Mercedonius (23 days) and two other intercalary months (33 and 34 days respectively) to the 355-day lunar year, to recalibrate the calendar in preparation for his calendar reform, which went into effect in 45 BC.

https://en.wikipedia.org/wiki/46_BC