I seem to recall a number like 1.1 kg. Don't go to the bank with that one, though.
Cross-checking, figuring that at $30/cubic inch, that's about $4,500 in printing charges at a commercial 3D printing service agency which is about right from what I remember of earlier calculations. I did it at $4.50/cubic inch for just materials cost and got $679, though, which is a bit higher than I remember.
I'd expect that about a kilogram is a good number, figuring a density of about that of water or so.