When `Number` is called without `new`, it's just a conversion function similar to `parseFloat`. There's no risk of contaminating the global space. (http://es5.github.io/#x15.7.1).

`parseInt` no longer parses `0...` strings as octal in ES5, btw. You do need to be wary of getting parsed as hex with `0x...` though. (http://es5.github.io/#x15.1.2.2).

Here's a useful comparison table: http://stackoverflow.com/a/17106702.