 1089 (number)

1089 is the integer after 1088 and before 1090.
1089 Cardinal One thousand and eightynine Ordinal 1089th Factorization Binary 10001000001 Hexadecimal 441 It is a square number (33 squared), a nonagonal number, a 32gonal number, a 364gonal number, and a centered octagonal number.
In base 10, the following steps always yield 1089:
 Take any threedigit number where the first and last digits differ by 2 or more.
 Reverse the digits, and subtract the smaller from the larger one.
 Add to this result the number produced by reversing its digits.
For example:
732 − 237 = 495 495 + 594 = 1089
Multiplying the number 1089 by the integers from 1 to 9 produces a pattern: multipliers adding up to 10 give products that are the digit reversals of each other. Also note the patterns within each column.
1 x 1089 = 1089 2 x 1089 = 2178 3 x 1089 = 3267 4 x 1089 = 4356 5 x 1089 = 5445 6 x 1089 = 6534 7 x 1089 = 7623 8 x 1089 = 8712 9 x 1089 = 9801
Numbers formed analogously in other bases, e.g. octal 1067 or hexadecimal 10EF, also have these properties.
1089 is the first reversedivisble number. The next is 2178 (= 1089 * 2 = 8712/4), and they are the only fourdigit numbers that are reverse divisible.
Other uses
 In the Rich Text Format, the language code 1089 indicates the text is in Swahili.^{[1]}
References
 ^ Microsoft, Microsoft Office Word 2007 Rich Text Format (RTF) Specification February (2007): 142. The hexadecimal number 441 (decimal 1089) is identified with "Kiswahili (Kenya)."
Categories: Integers
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