Brought to you by Maths Inspiration, this pencil is printed with the largest left-truncatable prime number 357686312646216567629137: this means it remains prime no matter how much you sharpen the pencil. 

A left-truncatable prime is a prime number that reminas prime even after you successvely remove its left most digit. 

These pencils come in a pack of 10

Watch James Grime explain more about truncatable prime numbers:

Price =  £10.97