Vampire Numbers Have Fangs For Factors

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Vampire numbers can have more than one pair of fangs! For example, 13,078,260 has three pairs: 1620 x 8073, 1863 x 7020, and 2070 x 6318. There are only seven four-digit vampire numbers, but there are more than 200 million vampire numbers that are 14 digits long or more. Pseudovampire numbers abide by the same rules, except that the fangs don't need to contain an equal number of digits. For example, 126 = 6 x 21.


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Key Facts In This Video

  1. See why 1,260 is a vampire number: 00:37

  2. 117,067 is a prime vampire number with prime fangs. 02:40

  3. In traditional folklore, vampires often suffered from arithmomania, or the compulsion to count. 03:47