Higher powers are 8000 (20³) kʰecʰe ('a ɡreat score') and jãːcʰe 160,000 (20⁴).
Then decades, however, are formed as unit–ten, as in Chinese, and the hundreds similarly.
20 is reported to be ɲiɕu, the same as vigesimal numeral 400; this may be lexical interference for the expected *ɲi-cu.
(In any case, there is no ambiguity, because as 400 it is obligatorily ɲiɕu ciː 'one 400'.)
Several of the decades have an epenthetic -p-, perhaps by analogy with 18 and 19, where the -p- presumably reflects a historical *cup 'ten':