Oprah Winfrey -- I'm Still a Cash Cow

Oprah may be on channel 1527 but it ain't stopping her "Favorite Things" from selling like hotcakes.

TMZ spoke with a bunch of the companies on the 2013 edition of O's famous list and every single one says it's already been huge for biz.

The power of Oprah's "Favorite Things" is nothing new ... but with her channel's problem attracting viewers in their target demo it's pretty impressive.

One company received 170 orders in 24 hours the day after the list was released ... and they haven't even put the magazine issue out yet.