How old was the man for whom Āryabhaṭa numeration is named when he wrote Āryabhaṭīya?
Āryabhaṭa numeration: The Āryabhaṭa numeration is a system of numerals based on Sanskrit phonemes. Aryabhata:  His works include the "Āryabhaṭīya" (499 CE, when he was 23 years old) and the "Arya-siddhanta".
i don't know