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Vampires are said to suffer from a condition called arithmomania: a compulsive desire to count things.

Vampires are said to have their own numbers: these are defined as a number that can be written as the product of two smaller numbers of half the length which contain all the digits of the larger number. For example 1395=15x93. The two smaller numbers are called the vampire number's fangs. Although this is little more than a numerical curiosity, mathematicians have proved that there are an infinite number of vampire numbers.

However, research into the science of Hallowe'en has also proved that vampires cannot exist. Vampires need to feed on the blood of a human being at least once a month to survive. The trouble is that once you have feasted on the human, the victim too becomes a vampire. So next month there are twice as many vampires in the search for human blood to feast on.

The world's population is estimated to be 6.7 billion. Each month the population of vampires doubles. Such is the devastating affect of doubling that within 33 months a single vampire would end up transforming the world's population into vampires. Even if one factors in the effect of the birthrate, humans can't reproduce quickly enough to counter the mathematical effect of doubling.

So forget the garlic and the mirrors, it's mathematics that is your best protection against the Prince of Darkness.

Marcus du Sautoy will be the new Simonyi Professor for the Public Understanding of Science at Oxford University, succeeding the evolutionist Richard Dawkins.

Excellent! We really need better public understanding of science, and if he can engage our interest with quirky snippets like that then there is hope.

(Headline - A 70-digit vampire number with 100025 different fang pairs)

## Comments

I don't disagree with your conclusion, but you seem to have missed an obvious error in Prof du Sautoy's argument. Not all victims of the vampire's bite become vampires - sometimes they just become rather drained corpses.

Indeed, I was always under the impression vampires tended only to "convert" young ladies wearing whispy but underwired nightgowns.

Posted by: The Remittance Man | October 29, 2008 9:24 AM