$(document).ready(function () {
    var table=$('#example').dataTable({"pageLength": 30});
    var tbl = $('#example').DataTable();
    alert(JSON.stringify(tbl.page.info()));
});

var table = $('#datatable_fixed_column')
                .DataTable({
 columns: [{....}],
"ajax": {....},
"initComplete": function (settings, json) {//here is the tricky part
                    var count = $('#my-table tr').length-1
                    $(".badge").html(count);
                }

table.data().length;