Convert Time Stamp from rosbag(Topic) to Understandable Format Y/M/D H:M:S

Hi @staff would you know what the following TimeStamp means? and how to convert it to seconds or other understable format such year/month/day Hour:Minutes:Seconds?

I have a car-robot that has driven 80 meters in about 1 min of simulation. However when I recorded the rosbag I had the:
First Timestamp =1,63277521885359E+018
and the
Last TimeStamp from this topic (odom) = 1,63277529735619E+018

I do not know to convert this data to an understandable format such as Y/M/D H:m:S
Some tool makes the trick? Or some Python Library such as DateTime (how to specific use, suitable class to apply?)

I have done some research here But these steps seem too complex rosbag/Cookbook - ROS Wiki

In addition, I got another column in my rosbag called field.header.sec
that intuitively should return the seconds. But assessing this data again. The first/end data are:

T0 = 7348
TF = 8036

Subtracting these values I have 688 seconds = 11 minutes. And this is Not realistic because I have killed the simulation and the rosbag after 2 minutes( max) and the car in the simulation achieved the goal after 1 min, not 11 minutes…
I wonder how to understand and convert the TimeStamp extracted from rosbags.
If someone could help me, I would be very grateful

Beginning of csv file (localizer or odom topic)

End of csv file

Hi @gvdhoorn has already assisted me on this

Thanks and sorry to duplicate here…
if someone needs something similar…the code is in this ROS answers link
I have just used Pandas and Datetime libraries