Vampire Numbers

Can you find vampire numbers in an interval?

uh...sure...umm...What's a Vampire Number?

Glad you asked!

If you search the idea out in Wolfram MathWorld you'll find that a vampire number is a number with an even number of digits (n) that can be factored into the product of two n/2 numbers called 'fangs.' The requirement is that the digits that make up the 'fangs' must be found in the original vampire number! For example:

1395 = 15 ✕ 93

(Both fangs may not end in a zero.)

Fill out the form below and find those vampires!

Vampire Hunter! You may see some vampires listed in a lime green color. Can you tell what makes them distinct from their other vampires?!

We had a recent visit with Copilot about Vampire Numbers and there were some surprises. Check out our chat.