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Cardinal | eighteen | |||
Ordinal | 18th (eighteenth) | |||
Numeral system | octodecimal | |||
Factorization | 2 × 32 | |||
Divisors | 1, 2, 3, 6, 9, 18 | |||
Greek numeral | ΙΗ´ | |||
Roman numeral | XVIII | |||
Binary | 100102 | |||
Ternary | 2003 | |||
Senary | 306 | |||
Octal | 228 | |||
Duodecimal | 1612 | |||
Hexadecimal | 1216 |
18 (eighteen) is the natural number following 17 and preceding 19.
In most countries, 18 is the age of majority, in which a minor becomes a legal adult. It is also the voting age, marriageable age, drinking age and smoking age in most countries, though sometimes these ages are different than the age of majority. Many websites restrict adult content to visitors who claim to be aged over 18.
2 (two) is a number, numeral and digit. It is the natural number following 1 and preceding 3. It is the smallest and only even prime number. Because it forms the basis of a duality, it has religious and spiritual significance in many cultures.
10 (ten) is the even natural number following 9 and preceding 11. Ten is the base of the decimal numeral system, the most common system of denoting numbers in both spoken and written language.
21 (twenty-one) is the natural number following 20 and preceding 22.
In number theory, an abundant number or excessive number is a positive integer for which the sum of its proper divisors is greater than the number. The integer 12 is the first abundant number. Its proper divisors are 1, 2, 3, 4 and 6 for a total of 16. The amount by which the sum exceeds the number is the abundance. The number 12 has an abundance of 4, for example.
30 (thirty) is the natural number following 29 and preceding 31.
90 (ninety) is the natural number following 89 and preceding 91.
84 (eighty-four) is the natural number following 83 and preceding 85.
36 (thirty-six) is the natural number following 35 and preceding 37.
48 (forty-eight) is the natural number following 47 and preceding 49. It is one third of a gross, or four dozens.
56 (fifty-six) is the natural number following 55 and preceding 57.
66 (sixty-six) is the natural number following 65 and preceding 67.
104 is the natural number following 103 and preceding 105.
100 or one hundred is the natural number following 99 and preceding 101.
220 is the natural number following 219 and preceding 221.
300 is the natural number following 299 and preceding 301.
360 is the natural number following 359 and preceding 361.
225 is the natural number following 224 and preceding 226.
1728 is the natural number following 1727 and preceding 1729. It is a dozen gross, or one great gross. It is also the number of cubic inches in a cubic foot.
240 is the natural number following 239 and preceding 241.
304 is the natural number following 303 and preceding 305.