How to use numeral.JS in this situation?

I am trying to use numeral.js to format my listener variable so numbers could be easily readable. But after I tried to use numeral.js the way it is, my function stops working. Can anyone please advise on what's wrong?

Trackster.renderTracks = function(tracks) {
  var $trackList = $("#track-list");

  $trackList.empty();

  for (var trackIndex = 0; trackIndex < tracks.length; trackIndex++) {
    var track = tracks[trackIndex];
    var mediumAlbumArt = track.image[1]["#text"];
    var formatListeners = numeral(track.listeners).format('0,0');

    var htmlTrackRow =
      '<div class="row track">' +
      '  <div class="col-xs-1 col-xs-offset-1 play-button">' +
      '    <a href="'+ track.url + '" target="_blank">' +
      '      <i class="fa fa-play-circle-o fa-2x"></i>' +
      '    </a>' +
      '  </div>' +
      '  <div class="col-xs-4">' + track.name + '</div>' +
      '  <div class="col-xs-2">' + track.artist + '</div>' +
      '  <div class="col-xs-2"><img src="' + mediumAlbumArt + '"/></div>' +
      '  <div class="col-xs-2">' + formatListeners + '</div>' +
      '</div>';

    $trackList.append(htmlTrackRow);
  }
};

Full Github Code is https://github.com/tfan1210/Trackster

Thanks!