any people have a fear of the number 13, but did you know that some believe the number 23 has mystical properties as well?   Those who believe the number is special say that anywhere you look, the number 23 plays an important role, from the Earth's axis (a 23-degree angle) to human reproduction (each parent contributes 23 chromosomes for a new human life).   In the psychological thriller The Number 23, Jim Carrey plays Walter Sparrow, a man whose life unravels after his wife Agatha (Virginia Madsen) gives him an obscure book for his birthday titled The Number 23. As Walter reads the book, about a brooding detective named Fingerling who is fixated with the digits, he becomes increasingly convinced its main character is based on his own life.   For Carrey, who is admittedly a "23rdian" (a person fascinated with the number 23) the role was meant to be -- even his production company is called JC23.   "I actually suggested Jim Carrey for the lead, but I didn't know that Jim was obsessed with 23," director Joel Schumacher told Tribute's Bonnie Laufer. "We had never discussed it and Jim and I had done Batman Forever together. I didn't know anything about his obsession with 23 until I got the script."   Despite the occasional dramatic role, Schumacher said Carrey eagerly embraced the chance to do something so different.   "Jim put himself through Hell. He definitely did. I mean he really tore it out of himself. It was sometimes painful to watch because he was going through such agony."   In the film, Carrey and Madsen play dual roles as Walter and Agatha, as well as the book's characters, Fingerling and Fabrizia, adding to their preparation.   "Jim embraced the darkness and the sexuality of the alter-ego and he designed this wonderful tattoo that he wears," Schumacher revealed. "He really got into it, the hair, the wardrobe, and so did Virginia. They really are two totally different human beings in the book than they are in life."   Now, as Walter's obsession with the number 23 begins to consume him, he becomes convinced that he is damned to the same fate as Fingerling and goes on a desperate quest to understand the mysteries within the book. If he can unlock the power behind the number 23, he just might be able to change his future. - Robin Stevenson