Given I have the number `1446309338000`, how do I create a JavaScript UTC date?

`new Date(1446309338000)` will equal a CST time (central standard) or local time.  

`new Date(Date.UTC(year, month, day, hour, minute, second))` haven't got this info yet.

Does JavaScript change the time if I do this?

```
new Date(1446309338000).ISOString();

```

Is it creating a new CST date and then converting it to UTC? I really just need the string. I am taking it from a database (RowKey from a Azure Table storage database).