Number Gossip
(Enter a number and I'll tell you everything you wanted to know about it but were afraid to ask.)
Unique Properties of 15
- 15 is the smallest emirpimes
- 15 is the smallest composite cyclic number, that is number n with the property that there is only one group of order n
- 15 is the magic constant of the unique order-3 normal magic square
- 15 is the number of letters in the words "uncopyrightable" and "dermatoglyphics", which are the only two longest words there are without repeating a letter
- 15 is the smallest product of twin primes