Brought to you by Maths Inspiration, this pencil is printed with the largest left-truncatable prime number: this means it remains prime no matter how much you sharpen the pencil.
357686312646216567629137 is itself prime, but so is 57686312646216567629137, and 7686312646216567629137, and so on all the way down to 7 which is, of course, also prime.
These pencils come in a pack of 11 (which is also prime, although sadly not truncatable. But it's very handy if you want to buy this gift for a football or cricket team!)
Watch James Grime explain more about truncatable prime numbers:
Price = p168 pence = £9.97