To find all the divisors of the number 42,240:
- 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 42,240:
The prime factorization of a number: finding the prime numbers that multiply together to make that number.
42,240 = 28 × 3 × 5 × 11
42,240 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 = (8 + 1) × (1 + 1) × (1 + 1) × (1 + 1) = 9 × 2 × 2 × 2 = 72
But to actually calculate the factors, see below...
2. Multiply the prime factors of the number 42,240
- 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
prime factor =
11
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 × 11 =
22
composite factor = 2
3 × 3 =
24
composite factor = 2 × 3 × 5 =
30
composite factor = 2
5 =
32
composite factor = 3 × 11 =
33
composite factor = 2
3 × 5 =
40
composite factor = 2
2 × 11 =
44
composite factor = 2
4 × 3 =
48
composite factor = 5 × 11 =
55
composite factor = 2
2 × 3 × 5 =
60
composite factor = 2
6 =
64
composite factor = 2 × 3 × 11 =
66
composite factor = 2
4 × 5 =
80
composite factor = 2
3 × 11 =
88
composite factor = 2
5 × 3 =
96
composite factor = 2 × 5 × 11 =
110
composite factor = 2
3 × 3 × 5 =
120
composite factor = 2
7 =
128
composite factor = 2
2 × 3 × 11 =
132
composite factor = 2
5 × 5 =
160
composite factor = 3 × 5 × 11 =
165
composite factor = 2
4 × 11 =
176
composite factor = 2
6 × 3 =
192
This list continues below...
... This list continues from above
composite factor = 2
2 × 5 × 11 =
220
composite factor = 2
4 × 3 × 5 =
240
composite factor = 2
8 =
256
composite factor = 2
3 × 3 × 11 =
264
composite factor = 2
6 × 5 =
320
composite factor = 2 × 3 × 5 × 11 =
330
composite factor = 2
5 × 11 =
352
composite factor = 2
7 × 3 =
384
composite factor = 2
3 × 5 × 11 =
440
composite factor = 2
5 × 3 × 5 =
480
composite factor = 2
4 × 3 × 11 =
528
composite factor = 2
7 × 5 =
640
composite factor = 2
2 × 3 × 5 × 11 =
660
composite factor = 2
6 × 11 =
704
composite factor = 2
8 × 3 =
768
composite factor = 2
4 × 5 × 11 =
880
composite factor = 2
6 × 3 × 5 =
960
composite factor = 2
5 × 3 × 11 =
1,056
composite factor = 2
8 × 5 =
1,280
composite factor = 2
3 × 3 × 5 × 11 =
1,320
composite factor = 2
7 × 11 =
1,408
composite factor = 2
5 × 5 × 11 =
1,760
composite factor = 2
7 × 3 × 5 =
1,920
composite factor = 2
6 × 3 × 11 =
2,112
composite factor = 2
4 × 3 × 5 × 11 =
2,640
composite factor = 2
8 × 11 =
2,816
composite factor = 2
6 × 5 × 11 =
3,520
composite factor = 2
8 × 3 × 5 =
3,840
composite factor = 2
7 × 3 × 11 =
4,224
composite factor = 2
5 × 3 × 5 × 11 =
5,280
composite factor = 2
7 × 5 × 11 =
7,040
composite factor = 2
8 × 3 × 11 =
8,448
composite factor = 2
6 × 3 × 5 × 11 =
10,560
composite factor = 2
8 × 5 × 11 =
14,080
composite factor = 2
7 × 3 × 5 × 11 =
21,120
composite factor = 2
8 × 3 × 5 × 11 =
42,240
72 factors (divisors)
What times what is 42,240?
What number multiplied by what number equals 42,240?
All the combinations of any two natural numbers whose product equals 42,240.
1 × 42,240 = 42,240
2 × 21,120 = 42,240
3 × 14,080 = 42,240
4 × 10,560 = 42,240
5 × 8,448 = 42,240
6 × 7,040 = 42,240
8 × 5,280 = 42,240
10 × 4,224 = 42,240
11 × 3,840 = 42,240
12 × 3,520 = 42,240
15 × 2,816 = 42,240
16 × 2,640 = 42,240
20 × 2,112 = 42,240
22 × 1,920 = 42,240
24 × 1,760 = 42,240
30 × 1,408 = 42,240
32 × 1,320 = 42,240
33 × 1,280 = 42,240
40 × 1,056 = 42,240
44 × 960 = 42,240
48 × 880 = 42,240
55 × 768 = 42,240
60 × 704 = 42,240
64 × 660 = 42,240
66 × 640 = 42,240
80 × 528 = 42,240
88 × 480 = 42,240
96 × 440 = 42,240
110 × 384 = 42,240
120 × 352 = 42,240
128 × 330 = 42,240
132 × 320 = 42,240
160 × 264 = 42,240
165 × 256 = 42,240
176 × 240 = 42,240
192 × 220 = 42,240
36 unique multiplications The final answer:
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