64
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.
By definition, a prime number has exactly two factors. So, there are no prime numbers with exactly three factors.
Composite numbers have more than two factors. So, the numbers which have two or less than two factors are not composite numbers. Numbers which have exactly two factors are prime numbers. 1 is an exceptional case because it is neither prime nor composite since it has only one factor which is 1.
Just 32.
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.
Square numbers, like 36 and 64.
There are four odd numbers less that 100 that have 6 factor. This does not compare with even numbers that have 12 factors!
There are 10 numbers less than 101 which have an odd number of factors: 1,4,9,16,25,36,49,64,81,100.
44 and 45 75 and 76 98 and 99
All but the square numbers - 53 of them.
2 and 4
Not only can they, but they must. An odd number cannot have an even factor. So none of the factors of either of the two odd numbers can be even and so the GCF is made up of only odd factors and so it must be odd.
None The even numbers 60, 72, 84, 90, and 96 each have 12 factors
Numbers that are prime can't be multiples of 10. Multiples of 10 can't be odd.
By some definitions prime numbers don't have proper factors. In other definitions, their only proper factor is 1. Either way, your answer is the next prime number after 50, which would be 53.
The proper factors of a number are all its factors except itself. Sometimes, the number 1 is also excluded. So, the proper factors of 6 are either 1, 2, and 3, or if excluding the number 1, they are 2 and 3. (If your instructor distinguishes between proper factors and proper divisors, then proper factors are all the factors of a number except 1 and itself, while proper divisors are all the factors of a number except itself, but often proper factors is the only term used, so check whether 1 is included in the definition you are using.)The list of factors in the question "What are the factors of the numbers from 1 to 100" (see link below) includes both 1 and the number itself, but if you remove the number itself, and the 1 if it is excluded in the definition of proper factor that you are using, you will have the complete list of proper factors.The prime numbers, which only have themselves and 1 as factors, are in bold in the list of factors on that page. Their proper factors are either the number 1, or if 1 is excluded, they have no proper factors.Short List of Proper Factors:As an example, here are the proper factors (including 1, which is sometimes used and sometimes not) for the first 10 numbers:1: No proper factors2: 13: 14: 1, 25: 16: 1, 2, 37: 18: 1, 2, 49: 1, 310: 1, 2, 5A less unwieldy versionIn practice, it seems unlikely that anyone wants you to continue the above list to 100. (That would be 3 sides of handwritten A4 paper.) Maybe they only wanted to know which numbers appear in the list of proper factors. For example, the proper factors of numbers from 1 to 10 are 1, 2, 3, 4 and 5 (as you can see above).