I don’t like Michael Douglas and this movie got lousy reviews so I doubt I’ll ever bother watching it.
But I’m curious as to what was the big secret with the six numbers. What did they turn out to be? Was Brittany Murphy really crazy or was she faking it?
The Butler did it.
Osiris beat me to it. 
Short answer: the girl’s father was buried in New York’s “Potter’s Field,” a mass cemetery for those who die in prison or on the streets, and whose bodies are never claimed. The number in the little girl’s head was the number of her father’s burial plot.
The book, by Andrew Klavan, is much more interesting than the movie, and it doesn’t have Michael Douglas in it. The book’s protagonist is a lot less arrogant and a lot more believable as a psychiatrist. They changed the whole nature of the “crazy” girl for the movie; she’s much more compelling in the book.
I didn’t think the book was that great when I read it–interesting, sure, but not fabulous…but it’s WAY better than the movie. These movies spoilers do not give away what’s in the book.
“I’ll never tell…”
Sorry, it had to be done.
Boromir is the bad guy