# 9 (number)

natural number

9 (nine) is the Arabic number which comes after 8 and before 10. It is an odd number, and is the highest single-digit number. It is also a square number. In Roman numerals, nine can be written as IX.

 ← 8 9 10 →
Cardinalnine
Ordinal9th
(ninth)
Numeral systemnonary
Factorization32
Greek numeralΘ´
Roman numeralIX
Unicode symbol(s)Ⅸ, ⅸ
Greek prefixennea-
Latin prefixnona-
Binary10012
Ternary1003
Quaternary214
Quinary145
Senary136
Octal118
Duodecimal912
Vigesimal920
Base 36936
Amharic
Arabicl٩
Urdu
Armenian numeralԹ
Bengali
Chinese/Japanese
/Korean numeral

Devanāgarī (Nao)
Greek numeralθ´
Hebrew numeralט (Tet)
Tamil numeral
Khmer
Telugu numeral
Thai numeral

The number also looks like an inverted 6. To tell the difference between the two, they are often underlined.

## Mathematics

The number nine (9) takes the shape of an upside-down six (6), is a multiple of 3, and the third square number after 4.

Nine is also a composite number, having the factors: 1, 3 and 9 itself. Nine is the first odd composite number