1 in 21,369,863

I often think, when I see the day's date on my computer screen, that there must be many people in the world celebrating their birthday that day. I enjoy playing with numbers so today I decided to try to work out how many people in the world would be celebrating their birthday on 15 November. It's a very rough and ready approach but I decided to divide the world's population of 7,800,000,000 (approx) by 365. So, by my estimation, 21,369,863 people are celebrating their birthday today and I only know one of them. SO . . .Happy birthday '1 in 21,369,863'.