This is the 82nd most frequent German word.
millionen
"Millionen" means "millions" in English.
Here, 'Millionen' is employed to express an enormous, unspecified number of euros in plural form, used directly with the currency noun.
Das Projekt kostete Millionen Euro.
The project cost millions of euros.
In this example, 'Millionen' indicates a large, exaggerated quantity (millions) to express hyperbole in a figurative sense.
Sie hat Millionen Bücher in ihrem Leben gelesen.
She has read millions of books in her life.
In this sentence, 'Millionen' is used as a plural form to denote an indefinite quantity (millions) of stars, exemplifying the use with the article 'von' to indicate 'of'.