Can one simply say miljoen without een? I think that is the case with both honderd and duizend.
I don't know how it is Dutch, however in German "Million" requires the article (”eine Million"), while you can leave it out before 100 and 1000.
It is the case with honderd and duizend but everyone I've asked says that miljoen needs the een.
Een miljoen schildpadden is niet genoeg!
'Tuurlijk, kan man niet te veel schildpadden hebben...
Is "één miljoen" also acceptable? Or do you always say "a million" rather than "one million."
Eén miljoen would be correct if the original sentence had been She has one million turtles. Normally one would say een miljoen, één miljoen is used to put extra emphasis that it is one million.
It does list the numeral "1" as acceptable, unfortunately.
Why is hebt instead of heeft incorrect here?
Hebt is only used in combination with je/jij/u.