This is the 15508th most frequent Russian word.
президентов
"Presidents" (genitive plural form in Russian).
The word 'президентов' is in the genitive plural form and is used to indicate possession or relation to the presidents.
Мы обсуждали достижения некоторых президентов страны.
We were discussing the achievements of some presidents of the country.
In this sentence, 'президентов' functions in a genitive plural form to specify the collection of individuals represented in the photos.
Фотографии всех президентов висят в музее.
The photographs of all the presidents hang in the museum.
Here, 'президентов' in genitive plural is used to denote a group of notable individuals whom the sentence highlights.