Brought to you by Maths Inspiration, this pencil is printed with the largest right-truncatable prime number: this means it remains prime no matter how much you sharpen the pencil.
73939133 is itself prime, but so is 7393913, and 739391, 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