This is the 14727th most frequent Russian word.
печей
"Печей" is the plural genitive form of "печь," meaning "stoves" or "ovens" in English.
Here, 'печей' functions as the genitive plural form, used in conjunction with the word 'количество' (quantity or number).
Количество печей в этой деревне уменьшилось за последние годы.
The number of stoves in this village has decreased over recent years.
In this context, 'печей' is used as the genitive plural form to describe the types of stoves featured in the exhibition.
В музее была выставка старинных печей.
There was an exhibition of antique stoves in the museum.
The word 'печей' is the genitive plural form of 'печь', indicating possession or relation to stoves in the phrase 'русских печей'.