Basically, I'd like to know what level each heading of an org file is and in what order they appear. So if my org file looks like this

* heading a
** sub-heading a.1
** sub-heading a.2
*** sub-sub-heading a.2.1
* heading b
** sub-heading b.1
*** sub-sub-heading b.1.1
* heading c

And an HTML export creates this

1 heading a
1.1 sub-heading a.1
1.2 sub-heading a.2
1.2.1 sub-sub-heading a.2.1
2 heading b
2.1 sub-heading b.1
2.1.1 sub-sub-heading b.1.1
3 heading c

is there a way to capture that prepended export numbering? Actually, I'd like to capture every heading's rank and order and keep it in a PROPERTIES drawer. There's obviously some baked in mechanism doing this for exporting. Is it possible for a mere mortal to know, have?