To find all the divisors of the number 75,990:
- 1. Decompose the number into prime factors.
- See how you can find out how many factors (divisors) the number has, without actually calculating them.
- 2. Multiply the prime factors in all their unique combinations, that yield different results.
1. Carry out the prime factorization of the number 75,990:
The prime factorization of a number: finding the prime numbers that multiply together to make that number.
75,990 = 2 × 3 × 5 × 17 × 149
75,990 is not a prime number but a composite one.
- Prime number: a natural number that is divisible (divided evenly) only by 1 and itself. A prime number has exactly two factors: 1 and the number itself.
- Examples of prime numbers: 2 (factors 1, 2), 3 (factors 1, 3), 5 (factors 1, 5), 7 (factors 1, 7), 11 (factors 1, 11), 13 (factors 1, 13), ...
- Composite number: a natural number that has at least one factor other than 1 and itself. So it is neither a prime number nor 1.
- Examples of composite numbers: 4 (it has 3 factors: 1, 2, 4), 6 (it has 4 factors: 1, 2, 3, 6), 8 (it has 4 factors: 1, 2, 4, 8), 9 (it has 3 factors: 1, 3, 9), 10 (it has 4 factors: 1, 2, 5, 10), 12 (it has 6 factors: 1, 2, 3, 4, 6, 12), ...
How to count the number of factors of a number?
Without actually finding the factors
- If a number N is prime factorized as:
N = am × bk × cz
where a, b, c are the prime factors and m, k, z are their exponents, natural numbers, .... - ...
- Then the number of factors of the number N can be calculated as:
n = (m + 1) × (k + 1) × (z + 1) - ...
- In our case, the number of factors is calculated as:
- n = (1 + 1) × (1 + 1) × (1 + 1) × (1 + 1) × (1 + 1) = 2 × 2 × 2 × 2 × 2 = 32
But to actually calculate the factors, see below...
2. Multiply the prime factors of the number 75,990
- Multiply the prime factors involved in the prime factorization of the number in all their unique combinations, that give different results.
- Also add 1 to the list of factors (divisors). All the numbers are divisible by 1.
All the factors (divisors) are listed below - in ascending order
The list of factors (divisors):
Numbers other than 1 that are not prime factors are composite factors (divisors).
neither prime nor composite =
1
prime factor =
2
prime factor =
3
prime factor =
5
composite factor = 2 × 3 =
6
composite factor = 2 × 5 =
10
composite factor = 3 × 5 =
15
prime factor =
17
composite factor = 2 × 3 × 5 =
30
composite factor = 2 × 17 =
34
composite factor = 3 × 17 =
51
composite factor = 5 × 17 =
85
composite factor = 2 × 3 × 17 =
102
prime factor =
149
composite factor = 2 × 5 × 17 =
170
composite factor = 3 × 5 × 17 =
255
This list continues below...
... This list continues from above
composite factor = 2 × 149 =
298
composite factor = 3 × 149 =
447
composite factor = 2 × 3 × 5 × 17 =
510
composite factor = 5 × 149 =
745
composite factor = 2 × 3 × 149 =
894
composite factor = 2 × 5 × 149 =
1,490
composite factor = 3 × 5 × 149 =
2,235
composite factor = 17 × 149 =
2,533
composite factor = 2 × 3 × 5 × 149 =
4,470
composite factor = 2 × 17 × 149 =
5,066
composite factor = 3 × 17 × 149 =
7,599
composite factor = 5 × 17 × 149 =
12,665
composite factor = 2 × 3 × 17 × 149 =
15,198
composite factor = 2 × 5 × 17 × 149 =
25,330
composite factor = 3 × 5 × 17 × 149 =
37,995
composite factor = 2 × 3 × 5 × 17 × 149 =
75,990
32 factors (divisors)
What times what is 75,990?
What number multiplied by what number equals 75,990?
All the combinations of any two natural numbers whose product equals 75,990.
1 × 75,990 = 75,990
2 × 37,995 = 75,990
3 × 25,330 = 75,990
5 × 15,198 = 75,990
6 × 12,665 = 75,990
10 × 7,599 = 75,990
15 × 5,066 = 75,990
17 × 4,470 = 75,990
30 × 2,533 = 75,990
34 × 2,235 = 75,990
51 × 1,490 = 75,990
85 × 894 = 75,990
102 × 745 = 75,990
149 × 510 = 75,990
170 × 447 = 75,990
255 × 298 = 75,990
16 unique multiplications The final answer:
(scroll down)