NumberOpedia

• 6 is the natural number following 5 and preceding 7. It is a composite number and the smallest perfect number.
• The only perfect number that can be sandwiched between twin primes 5 and 7.
• Binary representation of the number 6 is 110₂.
• 6 is the smallest number which is the product of two distinct primes: 6 = 2 × 3.
• The number 6 is the product and the sum of the same three numbers. It is the only number of that sort: 1+ 2 + 3 = 6 = 1 × 2 × 3.
• Factors of 6 are 1, 2, 3 and 6. 6 is the smallest composite number whose sum of prime factors is prime.
• The number 6 is a factorial number: 6 = 3! = 3 × 2 × 1.
• The number 6 can be written the sum of two cubes of rational numbers: 6 = (17/21)³ + (37/21)³.
• A cube has 6 faces.
• A six-sided polygon is a hexagon.
• A Golomb ruler of length 6 is a perfect ruler.
• Six of something is called a half-dozen because twelve is a dozen.
• In four dimensions, there are a total of six convex regular polytopes.
• A hexahedron is a polyhedron with six faces, with a cube being a special case.
• Hexameter is a poetic form consisting of six feet per line.
• People with sexdactyly have six fingers on each hand.
• A hex nut is a nut with six sides, and a hex bolt has a six-sided head.
• The measuring instrument called a sextant got its name because its shape forms one-sixth of a whole circle.
• A group of six musicians is called a sextet.
• Six babies delivered in one birth are sextuplets.
• The modern 6 can be traced back to the Brahmi numerals of India, which are first known from the Edicts of Ashoka c. 250 BCE.

• There are six feet in a fathom.
• A standard guitar has six strings.
• There are six whole tones in an octave.
• The probability that a number picked at random from the set of integers will have no repeated prime divisors is 6/π².