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.
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.
Numbers with exactly 6 factors are perfect squares of prime numbers. The prime factorization of a number with exactly 6 factors is in the form ( p^2 ), where ( p ) is a prime number. There are 10 prime numbers less than 30: 2, 3, 5, 7, 11, 13, 17, 19, 23, and 29. So, there are 10 numbers less than 30 that have exactly 6 factors.
Square numbers, like 36 and 64.
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.
That would be 1. The only factor of 1 is 1. All other whole numbers have at least two factors. Prime numbers have exactly two factors, while composite numbers have more than two 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.
Numbers with exactly 6 factors are perfect squares of prime numbers. The prime factorization of a number with exactly 6 factors is in the form ( p^2 ), where ( p ) is a prime number. There are 10 prime numbers less than 30: 2, 3, 5, 7, 11, 13, 17, 19, 23, and 29. So, there are 10 numbers less than 30 that have exactly 6 factors.
4
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.
11,22,33,44,55,66,77,88,99
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.