To find all the divisors of the number 1,287,825:
- 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 1,287,825:
The prime factorization of a number: finding the prime numbers that multiply together to make that number.
1,287,825 = 3 × 52 × 7 × 11 × 223
1,287,825 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 1,287,825
- 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 =
3
prime factor =
5
prime factor =
7
prime factor =
11
composite factor = 3 × 5 =
15
composite factor = 3 × 7 =
21
composite factor = 5
2 =
25
composite factor = 3 × 11 =
33
composite factor = 5 × 7 =
35
composite factor = 5 × 11 =
55
composite factor = 3 × 5
2 =
75
composite factor = 7 × 11 =
77
composite factor = 3 × 5 × 7 =
105
composite factor = 3 × 5 × 11 =
165
composite factor = 5
2 × 7 =
175
prime factor =
223
composite factor = 3 × 7 × 11 =
231
composite factor = 5
2 × 11 =
275
composite factor = 5 × 7 × 11 =
385
composite factor = 3 × 5
2 × 7 =
525
composite factor = 3 × 223 =
669
composite factor = 3 × 5
2 × 11 =
825
composite factor = 5 × 223 =
1,115
This list continues below...
... This list continues from above
composite factor = 3 × 5 × 7 × 11 =
1,155
composite factor = 7 × 223 =
1,561
composite factor = 5
2 × 7 × 11 =
1,925
composite factor = 11 × 223 =
2,453
composite factor = 3 × 5 × 223 =
3,345
composite factor = 3 × 7 × 223 =
4,683
composite factor = 5
2 × 223 =
5,575
composite factor = 3 × 5
2 × 7 × 11 =
5,775
composite factor = 3 × 11 × 223 =
7,359
composite factor = 5 × 7 × 223 =
7,805
composite factor = 5 × 11 × 223 =
12,265
composite factor = 3 × 5
2 × 223 =
16,725
composite factor = 7 × 11 × 223 =
17,171
composite factor = 3 × 5 × 7 × 223 =
23,415
composite factor = 3 × 5 × 11 × 223 =
36,795
composite factor = 5
2 × 7 × 223 =
39,025
composite factor = 3 × 7 × 11 × 223 =
51,513
composite factor = 5
2 × 11 × 223 =
61,325
composite factor = 5 × 7 × 11 × 223 =
85,855
composite factor = 3 × 5
2 × 7 × 223 =
117,075
composite factor = 3 × 5
2 × 11 × 223 =
183,975
composite factor = 3 × 5 × 7 × 11 × 223 =
257,565
composite factor = 5
2 × 7 × 11 × 223 =
429,275
composite factor = 3 × 5
2 × 7 × 11 × 223 =
1,287,825
48 factors (divisors)
What times what is 1,287,825?
What number multiplied by what number equals 1,287,825?
All the combinations of any two natural numbers whose product equals 1,287,825.
1 × 1,287,825 = 1,287,825
3 × 429,275 = 1,287,825
5 × 257,565 = 1,287,825
7 × 183,975 = 1,287,825
11 × 117,075 = 1,287,825
15 × 85,855 = 1,287,825
21 × 61,325 = 1,287,825
25 × 51,513 = 1,287,825
33 × 39,025 = 1,287,825
35 × 36,795 = 1,287,825
55 × 23,415 = 1,287,825
75 × 17,171 = 1,287,825
77 × 16,725 = 1,287,825
105 × 12,265 = 1,287,825
165 × 7,805 = 1,287,825
175 × 7,359 = 1,287,825
223 × 5,775 = 1,287,825
231 × 5,575 = 1,287,825
275 × 4,683 = 1,287,825
385 × 3,345 = 1,287,825
525 × 2,453 = 1,287,825
669 × 1,925 = 1,287,825
825 × 1,561 = 1,287,825
1,115 × 1,155 = 1,287,825
24 unique multiplications The final answer:
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