2 and 3
2 and 5
2 and 11
associative process
Factors are numbers you can multiply together to get another number. The factor pairs are: (1, 52) (2, 26) (4, 13)
Assuming the 36 numbers are all different, there are 36*35/2 = 630 pairs.
1 and 36 is one of two possible pairs -> so the squared numbers are 12 and 62
Factors are numbers you can multiply together to get another number. 21: (1, 21) (3, 7)
123456789
24
Co-prime numbers
Factors are numbers you can multiply together to get another number. 16: (1, 16) (2, 8) (4, 4)
Unless you specify a range, numbers keep on going. Theoretically, infinity has an infinite number of factor pairs.
The factors of all numbers can be written in pairs. With square numbers, one of those pairs is the same number twice. When listed singly, square numbers have an odd number of factors. All others are even.
Amicable pairs are two numbers that are related in such a way that total of the divisors of each is the same as the other number. This is the case of numbers 220 and 284.