setInterval Bug?

If I run the following code the setInterval fires straight away and continuously, it should only fire every hour:

function test(){
  console.log("Test Function");
}

setInterval(test, 60*60*1000);

If you change it to this so that it only runs every 24 hours it works OK:

function test(){
  console.log("Test Function");
}

setInterval(test, 24*60*60*1000);

Is this a bug?