$(...).datepicker is not a function - JQuery - Bootstrap

Question

I'm trying to include the datepicker for Bootstrap but am getting the following error:

Uncaught TypeError: $(...).datepicker is not a function

I don't see why it's there. I've looked at other cases of this error, but none match mine.

HTML:

<script src="https://code.jquery.com/jquery-2.2.4.min.js" integrity="sha256-BbhdlvQf/xTY9gja0Dq3HiwQF8LaCRTXxZKRutelT44=" crossorigin="anonymous"></script>
<script src="<?php echo BASE_URL; ?>/js/moment.min.js"></script>
<script src="<?php echo BASE_URL; ?>/js/bootstrap.min.js"></script>
<script src="<?php echo BASE_URL; ?>/js/bootstrap-datetimepicker.min.js"></script>
<script src="<?php echo BASE_URL; ?>/js/main.js"></script>

<div class="col-md-6">
    <div class="form-group">
         <label for="geboortedatum">Geboortedatum:</label>
         <div class="input-group datepicker" data-provide="datepicker">
               <input type="text" name="geboortedatum" id="geboortedatum" class="form-control">
               <div class="input-group-addon">
                   <span class="glyphicon glyphicon-th"></span>
               </div>
         </div>
    </div>
</div>

JS:

$(document).ready(function() {

    $('.datepicker').datepicker({
        format: 'dd/mm/yyyy'
    });
});

UPDATE after adding JQuery UI

It now looks like the following:

Answer 1

Need to include jquery-ui too:

<script src="//code.jquery.com/ui/1.11.4/jquery-ui.js"></script>

Answer 2

Not the right function name I think

$(document).ready(function() {

    $('.datepicker').datetimepicker({
        format: 'dd/mm/yyyy'
    });
});