How you be sure you get all the factors for a number?
There are ways, but not easy ones.The simpler is to go, very systematically, through all numbers from 2 to the number that you are trying to factorise. Skip numbers only if THEIR factors are not factors of your number.The other is to use prime factorisation. Any number can be broken down into a unit set of factors, some of which may feature more than once.For example, suppose your number is 72. Its prime factorisation is72 = 2*2*2*3*3 = 23*32Here you have 2 different prime factors, the first (= 2) appears 3 times and the second (= 3) appears twice. Remember that 2 and 21 are the same.Calculate all numbers of the form 2x3y where x = 0,1,2,3 and y = 0,1,2. The indices x and y go from 0 to the number of times the prime appears in the factorisation. This set of numbers, 2x3y, will be a complete list of all the factors of your number.