Tuesday, October 27, 2009

A Strange Prime Number - 73,939,133



The prime number 73,939,133 has a very strange property.

If you keep removing a digit from the right hand end of the number, each of the remaining numbers is also prime.
It's the largest number known with this property.

Take a look: 73,939,133 and 73,939,13 and 73,939,1 and 73,939 and 7,393 and 739 and 73 and 7 are all prime!