6 is the root of the 6-aliquot tree, and is itself the aliquot sum of only one number; the square number, 25. Six is the only number that is both the sum and the product of three consecutive positive numbers. Unrelated to 6's being a perfect number, a Golomb ruler of length 6 is a "perfect ruler". Six is a congruent number.
7 is a number, numeral, and glyph.. 7 or seven may also refer to: . AD 7, the seventh year of the AD era; 7 BC, the seventh year before the AD era; The month of July