τὸ πλῆθος οὐκ εὐαρίθμητον ἦν → the crowd wasn't easy to count, the crowd was not small, it was not a small crowd
ἀχειρί: ἐπίρρ., ἄνευ χειρῶν, ταῖς πύλαις ἀχειρί καὶ αὐτοματί αἴρεσθαι ἐπιτρέπομεν Ἐπιφάν. τ. 2. σ. 271D).