$ stat -c %Z examplefile 1289397609.000000000 stat (GNU coreutils) 8.6 installed from Arch Linux repos, executing in a bash shell.
This behavior changed recently - didn't used to have the .000000000 which breaks scripts that use stat. eg line 297: ((: 1289301692.000000000: syntax error: invalid arithmetic operator (error token is ".000000000")