16 (number) 0 to 15 in each column. Sixteen is an even number and a square number. Sixteen is the fourth power of two. Sixteen is the only integer that equals "m" and "n", for some unequal integers "m" and "n" ("m" = 4, "n" = 2, or vice versa). It has this property because 2 = 2 × 2. It is also equal to 2 (see tetration). 16 is the base of the hexadecimal number system, which is used extensively in computer science. In Spanish and Portuguese, 16 is the first compound number (Spanish: "dieciséis", European Portuguese: "dezasseis", Brazilian Portuguese: "dezesseis");
Factorial number system a separating mark between them (for instance by subscripting each digit by its base, also given in decimal, like 2010, this number also can be written as 2:0:1:0). In fact the factorial number system itself is not truly a numeral system in the sense of providing a representation for all natural numbers using only a finite alphabet of symbols. There is a natural mapping between the integers (or equivalently the numbers with "n" digits in factorial representation) and permutations of "n" elements in lexicographical order, when the integers are expressed in factoradic form. This mapping has been termed the Lehmer