To find all the divisors of the number 205,440:
- 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 205,440:
The prime factorization of a number: finding the prime numbers that multiply together to make that number.
205,440 = 27 × 3 × 5 × 107
205,440 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 = (7 + 1) × (1 + 1) × (1 + 1) × (1 + 1) = 8 × 2 × 2 × 2 = 64
But to actually calculate the factors, see below...
2. Multiply the prime factors of the number 205,440
- 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
composite factor = 2
2 =
4
prime factor =
5
composite factor = 2 × 3 =
6
composite factor = 2
3 =
8
composite factor = 2 × 5 =
10
composite factor = 2
2 × 3 =
12
composite factor = 3 × 5 =
15
composite factor = 2
4 =
16
composite factor = 2
2 × 5 =
20
composite factor = 2
3 × 3 =
24
composite factor = 2 × 3 × 5 =
30
composite factor = 2
5 =
32
composite factor = 2
3 × 5 =
40
composite factor = 2
4 × 3 =
48
composite factor = 2
2 × 3 × 5 =
60
composite factor = 2
6 =
64
composite factor = 2
4 × 5 =
80
composite factor = 2
5 × 3 =
96
prime factor =
107
composite factor = 2
3 × 3 × 5 =
120
composite factor = 2
7 =
128
composite factor = 2
5 × 5 =
160
composite factor = 2
6 × 3 =
192
composite factor = 2 × 107 =
214
composite factor = 2
4 × 3 × 5 =
240
composite factor = 2
6 × 5 =
320
composite factor = 3 × 107 =
321
composite factor = 2
7 × 3 =
384
composite factor = 2
2 × 107 =
428
This list continues below...
... This list continues from above
composite factor = 2
5 × 3 × 5 =
480
composite factor = 5 × 107 =
535
composite factor = 2
7 × 5 =
640
composite factor = 2 × 3 × 107 =
642
composite factor = 2
3 × 107 =
856
composite factor = 2
6 × 3 × 5 =
960
composite factor = 2 × 5 × 107 =
1,070
composite factor = 2
2 × 3 × 107 =
1,284
composite factor = 3 × 5 × 107 =
1,605
composite factor = 2
4 × 107 =
1,712
composite factor = 2
7 × 3 × 5 =
1,920
composite factor = 2
2 × 5 × 107 =
2,140
composite factor = 2
3 × 3 × 107 =
2,568
composite factor = 2 × 3 × 5 × 107 =
3,210
composite factor = 2
5 × 107 =
3,424
composite factor = 2
3 × 5 × 107 =
4,280
composite factor = 2
4 × 3 × 107 =
5,136
composite factor = 2
2 × 3 × 5 × 107 =
6,420
composite factor = 2
6 × 107 =
6,848
composite factor = 2
4 × 5 × 107 =
8,560
composite factor = 2
5 × 3 × 107 =
10,272
composite factor = 2
3 × 3 × 5 × 107 =
12,840
composite factor = 2
7 × 107 =
13,696
composite factor = 2
5 × 5 × 107 =
17,120
composite factor = 2
6 × 3 × 107 =
20,544
composite factor = 2
4 × 3 × 5 × 107 =
25,680
composite factor = 2
6 × 5 × 107 =
34,240
composite factor = 2
7 × 3 × 107 =
41,088
composite factor = 2
5 × 3 × 5 × 107 =
51,360
composite factor = 2
7 × 5 × 107 =
68,480
composite factor = 2
6 × 3 × 5 × 107 =
102,720
composite factor = 2
7 × 3 × 5 × 107 =
205,440
64 factors (divisors)
What times what is 205,440?
What number multiplied by what number equals 205,440?
All the combinations of any two natural numbers whose product equals 205,440.
1 × 205,440 = 205,440
2 × 102,720 = 205,440
3 × 68,480 = 205,440
4 × 51,360 = 205,440
5 × 41,088 = 205,440
6 × 34,240 = 205,440
8 × 25,680 = 205,440
10 × 20,544 = 205,440
12 × 17,120 = 205,440
15 × 13,696 = 205,440
16 × 12,840 = 205,440
20 × 10,272 = 205,440
24 × 8,560 = 205,440
30 × 6,848 = 205,440
32 × 6,420 = 205,440
40 × 5,136 = 205,440
48 × 4,280 = 205,440
60 × 3,424 = 205,440
64 × 3,210 = 205,440
80 × 2,568 = 205,440
96 × 2,140 = 205,440
107 × 1,920 = 205,440
120 × 1,712 = 205,440
128 × 1,605 = 205,440
160 × 1,284 = 205,440
192 × 1,070 = 205,440
214 × 960 = 205,440
240 × 856 = 205,440
320 × 642 = 205,440
321 × 640 = 205,440
384 × 535 = 205,440
428 × 480 = 205,440
32 unique multiplications The final answer:
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