The number 18

Representation numerals

Greek numeral

ιηʹ

Arabic numeral

١٨

Roman numeral

XVIII

Maya numeral

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Chinese numeral

十八

Hebrew numeral

חי
Numeral systems
Binary: 10010
Septimal (base 7): 24
Octal: 22
Hexadecimal: 12
Base 24: I
Factorization
18 = 2 × 3 × 3
18 has 6 divisors: 1, 2, 3, 6, 9, 18
Sum of all divisors other than 18: 21
Sums & differences
Sum of 2 squares: 18 = 32 + 32
Goldbach conjecture: 18 = 13 + 5 = 11 + 7
Characteristics
18 is a heptagonal number
Related primes
The 18th prime number is: 61
Previous prime number: 17 — Next prime number: 19
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