Calculate the number 5187

After delivering a speech at an elementary school, the president lets the kids ask a few questions. One little boy, Joe raises his hand and asks, “How come you invaded Iraq without the support of the United Nations?”
Just as the president begins to answer, the recess bell rings and he says they’ll continue afterward. 25 minutes later the kids come back to class.
“Where were we?” says the president. “Oh, yes… do you kids have any questions?”
Another boy raises his hand and says, “I have three questions: First, why did you invade Iraq without support from the U.N.? Second, why did the recess bell go off 30 minutes early? And third, where is my buddy Joe?”