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7 (seven) is the natural number following 6 and preceding 8. It is the only prime number preceding a cube.
The seven Classical planets resulted in seven being the number of days in a week. It is often considered lucky in Western culture and is often seen as highly symbolic. Unlike Western culture, in Vietnamese culture, the number seven is sometimes considered unlucky.It is the first number whose pronunciation contains more than one syllable, not counting 0.

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