11,22,33,44,55,66,77,88,99
If the GCF of a given pair of numbers is 1, the LCM will be equal to their product. If the GCF is greater than 1, the LCM will be less than their product. Or, stated another way, if the two numbers have no common prime factors, their LCM will be their product.
4, 9, 25 and 49 They are squares of prime numbers.
There are 10 numbers less than 101 which have an odd number of factors: 1,4,9,16,25,36,49,64,81,100.
144, 121 and 100
1 is the number less than fifty with the fewest number of factors. All other numbers have at least two factors (1, and the integer itself).
Prime numbers
They all are prime numbers except 1
There are a few numbers that are less than 19 and have more than 4 factors. The number 10 is less than 19 and has more than four factors.
If the two numbers have no common factors other than 1, the LCM will be their product. If there are other common factors, the LCM will be less.
The ones with less than three factors.
Four numbers less than thirty, 12, 18, 20, and 28, each have exactly 6 factors.
There are 12 numbers less than 150 which have an odd number of factors: 1,4,9,16,25,36,49,64,81,100,121,144.
10,20,30,40,50,60,70,80,90
The numbers for which the sum of its proper factors is 1 less than the number is the powers of 2; less than 50 these are: 2, 4, 8, 16 & 32.
If the GCF of a given pair of numbers is 1, the LCM will be equal to their product. If the GCF is greater than 1, the LCM will be less than their product. Or, stated another way, if the two numbers have no common prime factors, their LCM will be their product.
All of the numbers less than six can be factors, and all integers have a least one factor that is less than six. Here's a set of factors less than 6: (1, 2, 3, 4, 5)
There are 31 numbers less than 1,000 which have an odd number of factors. They are: 1,4,9,16,25,36,49,64,81,100,121,144,169,196,225,256,289,324,361,400,441,484,529,576,625,676,729,784,841,900,961.