Pseudovampire numbers

On April 29, 1994,1 challenged computer scientists and mathematicians around the world to submit the largest vampire number they could find. It turns out that there are certain situations in which arbitrarily large, pseudovampire numbers can be found. Pseudovampires are numbers that have the same properties as vampires, but the two multiplicands have a different number of digits. After reading my chal-... 

Upon hearing of my interest in vampire numbers, Tony Davie from Scotland found other four-digit pseudovampires. He wrote the following Gofer program to perform the search ... 

What is the largest true vampire number you can find lurking out there in the world of integers Glenn S. Knickerbocker from New York notes that no vampires or pseudovampires are products of two vampires or pseudovampires with six or fewer digits. 

---