Here are some facts about 28:
28 is a PERFECT NUMBER. A perfect number is a number that is equal to the sum of its proper factors. A proper factor is any number that divides evenly into another number other than the number itself. What numbers divide evenly into 28 other than 28 itself? 1, 2, 4, 7, 14. And if you add them up, what do you get? 28!! The first five perfect numbers are 6, 28, 496, 8128, and 33550336.
28 is a HAPPY NUMBER in base 10. A happy number means that if you square each digit and add the squares, then do the same with the sum, eventually you will get to 1. 2 squared + 8 squared = 68. 6 squared + 8 squared = 100. 1 squared + 0 squared + 0 squared = 1.
People think the moon's cycle is 28 days long, but it is really about 29.5 days.
In Hebrew numerology, the word כח, which means "strength" has a numerical value of 28.
There are 28 letters in the Esperanto alphabet.
Jewish tradition holds that the sun moves in a 28 year cycle. The prayer Birchat HaChama is said one day every 28 years when the sun returns to it's starting point from creation.
And it was 28 years ago today that I gave birth to my daughter. HAPPY BIRTHDAY KIDDO!!