CC Madhya 21.67

daśa-biśa-śata-sahasra-ayuta-lakṣa-vadana
koṭy-arbuda mukha kāro, nā yāya gaṇana
Word for word: 
daśa — ten; biśa — twenty; śata — hundred; sahasra — thousand; ayuta — ten thousand; lakṣa — a hundred thousand; vadana — faces; koṭi — ten million; arbuda — a hundred million; mukha — faces; kāro — of some of them; yāya gaṇana — not possible to count.
Translation: 
“These Brahmās had different numbers of heads. Some had ten heads, some twenty, some a hundred, some a thousand, some ten thousand, some a hundred thousand, some ten million and others a hundred million. No one can count the number of faces they had.