How do you format LastModifiedDate for a Wiki Page update

I'm working on a script to update a bunch of Wiki Pages which have some incorrect data in the HTML body. I've got the script pretty much how I want it, but would rather..

1. It didn't send any notifications.. pretty sure this isn't in the Script API.. and I'd have to use ExecuteScript and set it to turn off notifications?

2. It sets the LastModifiedDate to the CreatedDate. The docs say it's expecting that field to be Int32 (not DateTime, which I'm getting from CreatedDate)..

#set($wikiCreateDttm = $wiki.CreatedDate)
#set($wikiBody= "Hello")
#set($wikiUpdated = $core_v2_wikiPage.Update(27377, "%{ Body = $wikiBody, LastModifiedDate = $wikiCreateDttm }"))

I can't just take the CreatedDate as is, but how to I get it into a format that works with LastModifiedDate?

Thanks!