Prime numbers are special numbers, greater than 1, that have exactly two factors, themselves and 1. 19 is a prime number. It can only be divided by 1 and 19. 9 is not a prime number. It can be ...

One of my favorite anecdotes about prime numbers concerns Alexander Grothendieck, who was among the most brilliant mathematicians of the 20th century. According to one account, he was once asked ...