If you want to use a number as search term you must convert it as string like:
$(document).ready(function () {
var numbers;
numbers = new Bloodhound({
datumTokenizer: function (d) {
return Bloodhound.tokenizers.whitespace(d.value.toString());
},
queryTokenizer: Bloodhound.tokenizers.whitespace,
local: [{ "value": 1 , "text": "A"}, { "value": 2 , "text": "C+E"}]
});
numbers.initialize();
$('.typeahead').typeahead(null, {
displayKey: 'value',
source: numbers.ttAdapter()
});
});