Output the total number of rows in a view
You can add a custom section to either the header or footer to do this.


Edit the view / display.
In the center section, click Add next to Header or Footer.
Choose Global: Result Summary.  Add it where you need it.
Then, edit the textarea to be the format that you need.  There are a bunch of tokens available for building up the numbers.
Preview the view, and then Save if everything is OK.