18 (number)
natural number
18 (eighteen) is a number. It comes between seventeen and nineteen, and is an even number. It is divisible by 1, 2, 3, 6, 9 and 18. In most countries it is the age of majority, age of consent, and voting age.
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Cardinal | eighteen | |||
Ordinal | 18th (eighteenth) | |||
Factorization | 2 × 32 | |||
Greek numeral | ΙΗ´ | |||
Roman numeral | XVIII | |||
Binary | 100102 | |||
Ternary | 2003 | |||
Quaternary | 1024 | |||
Quinary | 335 | |||
Senary | 306 | |||
Octal | 228 | |||
Duodecimal | 1612 | |||
Hexadecimal | 1216 | |||
Vigesimal | I20 | |||
Base 36 | I36 |
In Roman numerals, 18 is written as XVIII.
The number 18 has many multiples such as: 36, 54, 72, 90, 108, and so on. The prime factorization of 18 is 3x3x2 in expanded form, and 2x3² in factored form.