To find all the divisors of the number 120,870:
- 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 120,870:
The prime factorization of a number: finding the prime numbers that multiply together to make that number.
120,870 = 2 × 32 × 5 × 17 × 79
120,870 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) × (2 + 1) × (1 + 1) × (1 + 1) × (1 + 1) = 2 × 3 × 2 × 2 × 2 = 48
But to actually calculate the factors, see below...
2. Multiply the prime factors of the number 120,870
- Multiply the prime factors involved in the prime factorization of the number in all their unique combinations, that give different results.
- Also consider the exponents of these prime factors.
- 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 = 3
2 =
9
composite factor = 2 × 5 =
10
composite factor = 3 × 5 =
15
prime factor =
17
composite factor = 2 × 3
2 =
18
composite factor = 2 × 3 × 5 =
30
composite factor = 2 × 17 =
34
composite factor = 3
2 × 5 =
45
composite factor = 3 × 17 =
51
prime factor =
79
composite factor = 5 × 17 =
85
composite factor = 2 × 3
2 × 5 =
90
composite factor = 2 × 3 × 17 =
102
composite factor = 3
2 × 17 =
153
composite factor = 2 × 79 =
158
composite factor = 2 × 5 × 17 =
170
composite factor = 3 × 79 =
237
composite factor = 3 × 5 × 17 =
255
composite factor = 2 × 3
2 × 17 =
306
This list continues below...
... This list continues from above
composite factor = 5 × 79 =
395
composite factor = 2 × 3 × 79 =
474
composite factor = 2 × 3 × 5 × 17 =
510
composite factor = 3
2 × 79 =
711
composite factor = 3
2 × 5 × 17 =
765
composite factor = 2 × 5 × 79 =
790
composite factor = 3 × 5 × 79 =
1,185
composite factor = 17 × 79 =
1,343
composite factor = 2 × 3
2 × 79 =
1,422
composite factor = 2 × 3
2 × 5 × 17 =
1,530
composite factor = 2 × 3 × 5 × 79 =
2,370
composite factor = 2 × 17 × 79 =
2,686
composite factor = 3
2 × 5 × 79 =
3,555
composite factor = 3 × 17 × 79 =
4,029
composite factor = 5 × 17 × 79 =
6,715
composite factor = 2 × 3
2 × 5 × 79 =
7,110
composite factor = 2 × 3 × 17 × 79 =
8,058
composite factor = 3
2 × 17 × 79 =
12,087
composite factor = 2 × 5 × 17 × 79 =
13,430
composite factor = 3 × 5 × 17 × 79 =
20,145
composite factor = 2 × 3
2 × 17 × 79 =
24,174
composite factor = 2 × 3 × 5 × 17 × 79 =
40,290
composite factor = 3
2 × 5 × 17 × 79 =
60,435
composite factor = 2 × 3
2 × 5 × 17 × 79 =
120,870
48 factors (divisors)
What times what is 120,870?
What number multiplied by what number equals 120,870?
All the combinations of any two natural numbers whose product equals 120,870.
1 × 120,870 = 120,870
2 × 60,435 = 120,870
3 × 40,290 = 120,870
5 × 24,174 = 120,870
6 × 20,145 = 120,870
9 × 13,430 = 120,870
10 × 12,087 = 120,870
15 × 8,058 = 120,870
17 × 7,110 = 120,870
18 × 6,715 = 120,870
30 × 4,029 = 120,870
34 × 3,555 = 120,870
45 × 2,686 = 120,870
51 × 2,370 = 120,870
79 × 1,530 = 120,870
85 × 1,422 = 120,870
90 × 1,343 = 120,870
102 × 1,185 = 120,870
153 × 790 = 120,870
158 × 765 = 120,870
170 × 711 = 120,870
237 × 510 = 120,870
255 × 474 = 120,870
306 × 395 = 120,870
24 unique multiplications The final answer:
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