Chrono duration to time string

I have a few lines of code that takes the system clock on my Windows machine and converts it to a double.

std::chrono::time_point<std::chrono::system_clock> currentNow = 
std::chrono::system_clock::now();
auto duration = currentNow.time_since_epoch();
double millis = static_cast<double>(std::chrono::duration_cast<std::chrono::milliseconds>(duration).count());
double origin_time = millis / 1000;

I would like to reverse this later on and convert the double to a string being the format YYYY-mm-dd HH:MM:SS.ffffffff

The first step I have right now is taking the double and passing it as a parameter to chrono::duration.

auto rep = std::chrono::duration<double>(origin_time);

How would I go about using the chrono library to achieve the string specified above, thanks!