Actually 27 HP but ratings today are a lot of smoke and mirrors. i just bought the 445, and what did it for me was the 4 year 300 HR vs 2 yr 120 HR warranty that i received with the 445. Have been able to cut the lawn only once since i brought it home last week (raining since then) but lawn cutting time was cut in 1/2. That's not a typo. I purchased mine with the mulching kit installed.
Tom
I should also add that I have been contemplating this since last year, and when i finally walked into my local dealer last monday, he had a 445 there with a seat from the 600 series. Sent from the factory like that. Seeing as I'm a fairly big guy ( 6'2" 260 lb) I jumped all over this. 21" seat back is beautiful Good score on my part