This is the 16626th most frequent Russian word.
семерых
"Семерых" means "seven people" (genitive or accusative form).
The word 'семерых' is used in the accusative case, referring to the seven friends being seen.
Я видел семерых друзей в парке.
I saw seven friends in the park.
The word 'семерым' is used in the dative case, reflecting the recipients of the gifts.
Они подарили подарки семерым людям.
They gave gifts to seven people.
The word 'семерых' is used in the genitive case, specifying the group of children being talked about.