Is the time span correctly converted to milliseconds?

Question

Database

Please explain how it turns out that only 1387263000 milliseconds have passed from January 1, 2011 00:00 hours to September 9, 2011 05:00 hours?
The original (from the article) read:
"Let's walk through an example: let's say it's September 9th, 2011, at 5:00pm and our 'epoch' begins on January 1st, 2011. There have been 1387263000 milliseconds since the beginning of our epoch, so to start our ID, we fill the left-most 41 bits with this value with a left-shift:"

Answer 1

Well, some bullshit. This number of milliseconds is just over 16 days