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.[citation needed] 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.[citation needed] It is the first number whose pronunciation contains more than one syllable, not counting 0.