There are not always an even number of factor pairs of a number - for example, prime numbers have an even number of factors, because they are divisible by themselves and 1, but this is only one pair of factors. However, for any square number, (for example, 3 x 3 = 9, 4 x 4 = 16), at least one of these factor pairs will consist of the same number repeated twice.
These are the 16 factor pairs for the number 1,080:1080,1540,2360,3270,4216,5180,6135,8120,9108,1090,1272,1560,1854,2045,2440,2736,30
The factor pairs of 21 are:1, 213, 7Therefore, the number 21 has two pairs of positive integer factors.
All of the composite numbers less than 100 have factor pairs.
One divides any number
As I understand it, the number of factor pairs is equal to the number of rectangles.
its a factor with two pairs of the same number
These are the 16 factor pairs for the number 1,080:1080,1540,2360,3270,4216,5180,6135,8120,9108,1090,1272,1560,1854,2045,2440,2736,30
A square number has an odd number of factors, but a number with an odd number of factor pairs is nothing special.
Number of factor pairs = number of rectangles
The number 18.
76 has 3 factor pairs: (1,76), (2,38), (4,19).
12 and 18 have three factor pairs.
12 and 18 have three factor pairs.
The factor pairs of 16 are (16,1)(8,2)(4,4)
One pair: it's a prime number.
Unless you specify a range, numbers keep on going. Theoretically, infinity has an infinite number of factor pairs.
The only single things that can be pairs are pants, scissors and glasses. The number 60 can be broken down into factor pairs, but is not a factor pair by itself.