This is the 459th most frequent Finnish word.
hyvinkin
"Hyvinkin" means "quite possibly" or "even very."
Here 'hyvinkin' is used to emphasize the adjective 'mielenkiintoinen' (interesting), conveying a stronger intensity than 'very'.
Tämä kirja on hyvinkin mielenkiintoinen.
This book is very interesting.
In this case, 'hyvinkin' is utilized to emphasize 'ajoissa' (on time), suggesting a possibility of being even earlier than typical timing.
Hän saattaa saapua hyvinkin ajoissa.
He might arrive quite early.
Here, 'hyvinkin' enhances the adjective 'hyödyllisiä' (useful), showing a higher probability or intensity of usefulness.