Get value attribute of the clicked checkbox via JQuery

I have got this checkbox which has value 1.

<input type="checkbox" name="option_1" id="checkbox_1" value="1">

Also I use this method to make checked/unchecked it.

$('input[id^="checkbox_"]').not('#checkbox_all').click(function () {
            $('#checkbox_all').prop('checked', false);

    // Get 'VALUE' of the checkbox here   

});

What I need is somehow get 'VALUE' of the clicked checkbox. So In that case it should be 1.

Any clue how do it could be done?

Thank you!