I did mean the films, yes, as the first Harry Potter book is also beyond 20 years.
It’s definitely impressive to see how fast time times flies by. If I have counted the days correctly, the Halo franchise should be 7305 days old. This number has the factors 1, 3, 5, 15, 487, 1461, 2435 and 7305 where 3, 5 and 487 are prime factors. There may also exist few other interesting facts related to this number that are less obvious.
Finally, we should not forget to celebrate the following anniversaries.
- 14 Feb 2022 | 7396 days (86^2)
- 6 Aug 2022 | 7569 days (87^2)
- 28 Jan 2023 | 7744 days (88^2)
- 1 Mar 2023 | 7776 days (6^5, perfect power, 7777-1)
- 24 Jul 2023 | 7921 days (89^2, prime power)
- 11 Oct 2023 | 8000 days (20^3)
There may also exist other occasions that are worth celebrating like prime anniversaries and anniversaries related to specific number weeks, hours, minutes or seconds.
HAPPY BIRTHDAY HALO!
It’s been a long journey! And I’m glad to have been part of it.
Happy Birthday Halo, you beauty
Happy birthday, Halo!!! 
I was lucky enough to be working at Microsoft 25 years ago in the first Xbox Games group. The Launch was a great time.
LFG love it . Infinite is Pogslam
O happy birthday! Greetings from Norway! Fight on, enjoy the show with a fire in our hearts! Gonna muliplayer so bad now! Have fun all you too!
I wish I could play the glorious gift that was bestowed upon us today, but I am currently stuck at work 
One more year and John Halo can legally drink beer.
I can still remember playing my first level of CE. The Masterchief emerged from the crashed escape pod and I saw the Ring emerging in the distance and was hooked!
The people who had fun immediately switching to a pistol and 3 shooting someone over the AR start knew this was going to be a fun ride. We shall forget the disaster of H2 BXR button mashing and the perfection of Halo 3.
All other Halo titles are fun evolutions, but those three games? Solidified we needed to make this a 30-40 year game franchise. Still pushing for the original dream of world domination. Next stop- Beating WoW online numbers in 24 hours! /s
There’s been plenty of up and down memories made that’s for sure. Happy birthday.
I remember that first time heading to a party and some folks brought this strange Xbox and played Pillar of Autumn. I asked if I can go next and when they got to crash land on Halo I felt the Duke controller.
I fell in love and the rest is history.
Such a legendary series I thought would be a fun time once I got the console the following day and turned out to be such a big hit
Happy Birthday Halo!