Convert time to integer in Php

How would you convert time to integer?

 string(8) "04:04:07"

I want this as 4(hours) or much better 4.04(4hours and 4 minutes)

I tried

  $yourdatetime = "04:04:07";
  $timestamp = strtotime($yourdatetime);

Which results in

 int(1458590887)