Calculate the number 3909

Jack wakes up with a huge hangover after attending his company's Christmas Party. Jack is not normally a drinker, but the drinks didn't taste like alcohol at all. He didn't even remember how he got home from the party. As bad as he was feeling, he wondered if he did something wrong.
Jack had to force himself to open his eyes, and the first thing he sees is a couple of aspirins next to a glass of water on the side table. And, next to them, a single red rose! Jack sits up and sees his clothing in front of him, all clean and pressed. He looks around the room and sees that it is in perfect order, spotlessly clean. So is the rest of the house.
He takes the aspirins, cringes when he sees a huge black eye staring back at him in the bathroom mirror. Then he notices a note hanging on the corner of the mirror written in red with little hearts on it and a kiss mark from his wife in lipstick: "Honey, breakfast is on the stove, I left early to get groceries to make your favorite dinner tonight. I love you, darling! Love, Jillian"
He stumbles into the kitchen and sure enough, there is a hot breakfast, steaming hot coffee, and the morning newspaper all waiting for him. His son is also at the table, eating. Jack asks, "Son... what happened last night?"
"Well, you came home after 3 in the morning, drunk and out of your mind. You fell over the coffee table and broke it, and then you puked in the hallway, and got that black eye when you ran into the door."
Confused, he asked his son, "So, why is everything in such perfect order and so clean? I have a rose, and breakfast is on the table waiting for me?"

His son replies, "Oh THAT! Well, Mom dragged you to the bedroom, and when she tried to take your pants off, you screamed,'Leave me alone, I'm married!'"