To find all the divisors of the number 21,600:
- 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 21,600:
The prime factorization of a number: finding the prime numbers that multiply together to make that number.
21,600 = 25 × 33 × 52
21,600 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 = (5 + 1) × (3 + 1) × (2 + 1) = 6 × 4 × 3 = 72
But to actually calculate the factors, see below...
2. Multiply the prime factors of the number 21,600
- 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 = 3
2 =
9
composite factor = 2 × 5 =
10
composite factor = 2
2 × 3 =
12
composite factor = 3 × 5 =
15
composite factor = 2
4 =
16
composite factor = 2 × 3
2 =
18
composite factor = 2
2 × 5 =
20
composite factor = 2
3 × 3 =
24
composite factor = 5
2 =
25
composite factor = 3
3 =
27
composite factor = 2 × 3 × 5 =
30
composite factor = 2
5 =
32
composite factor = 2
2 × 3
2 =
36
composite factor = 2
3 × 5 =
40
composite factor = 3
2 × 5 =
45
composite factor = 2
4 × 3 =
48
composite factor = 2 × 5
2 =
50
composite factor = 2 × 3
3 =
54
composite factor = 2
2 × 3 × 5 =
60
composite factor = 2
3 × 3
2 =
72
composite factor = 3 × 5
2 =
75
composite factor = 2
4 × 5 =
80
composite factor = 2 × 3
2 × 5 =
90
composite factor = 2
5 × 3 =
96
composite factor = 2
2 × 5
2 =
100
composite factor = 2
2 × 3
3 =
108
composite factor = 2
3 × 3 × 5 =
120
composite factor = 3
3 × 5 =
135
composite factor = 2
4 × 3
2 =
144
This list continues below...
... This list continues from above
composite factor = 2 × 3 × 5
2 =
150
composite factor = 2
5 × 5 =
160
composite factor = 2
2 × 3
2 × 5 =
180
composite factor = 2
3 × 5
2 =
200
composite factor = 2
3 × 3
3 =
216
composite factor = 3
2 × 5
2 =
225
composite factor = 2
4 × 3 × 5 =
240
composite factor = 2 × 3
3 × 5 =
270
composite factor = 2
5 × 3
2 =
288
composite factor = 2
2 × 3 × 5
2 =
300
composite factor = 2
3 × 3
2 × 5 =
360
composite factor = 2
4 × 5
2 =
400
composite factor = 2
4 × 3
3 =
432
composite factor = 2 × 3
2 × 5
2 =
450
composite factor = 2
5 × 3 × 5 =
480
composite factor = 2
2 × 3
3 × 5 =
540
composite factor = 2
3 × 3 × 5
2 =
600
composite factor = 3
3 × 5
2 =
675
composite factor = 2
4 × 3
2 × 5 =
720
composite factor = 2
5 × 5
2 =
800
composite factor = 2
5 × 3
3 =
864
composite factor = 2
2 × 3
2 × 5
2 =
900
composite factor = 2
3 × 3
3 × 5 =
1,080
composite factor = 2
4 × 3 × 5
2 =
1,200
composite factor = 2 × 3
3 × 5
2 =
1,350
composite factor = 2
5 × 3
2 × 5 =
1,440
composite factor = 2
3 × 3
2 × 5
2 =
1,800
composite factor = 2
4 × 3
3 × 5 =
2,160
composite factor = 2
5 × 3 × 5
2 =
2,400
composite factor = 2
2 × 3
3 × 5
2 =
2,700
composite factor = 2
4 × 3
2 × 5
2 =
3,600
composite factor = 2
5 × 3
3 × 5 =
4,320
composite factor = 2
3 × 3
3 × 5
2 =
5,400
composite factor = 2
5 × 3
2 × 5
2 =
7,200
composite factor = 2
4 × 3
3 × 5
2 =
10,800
composite factor = 2
5 × 3
3 × 5
2 =
21,600
72 factors (divisors)
What times what is 21,600?
What number multiplied by what number equals 21,600?
All the combinations of any two natural numbers whose product equals 21,600.
1 × 21,600 = 21,600
2 × 10,800 = 21,600
3 × 7,200 = 21,600
4 × 5,400 = 21,600
5 × 4,320 = 21,600
6 × 3,600 = 21,600
8 × 2,700 = 21,600
9 × 2,400 = 21,600
10 × 2,160 = 21,600
12 × 1,800 = 21,600
15 × 1,440 = 21,600
16 × 1,350 = 21,600
18 × 1,200 = 21,600
20 × 1,080 = 21,600
24 × 900 = 21,600
25 × 864 = 21,600
27 × 800 = 21,600
30 × 720 = 21,600
32 × 675 = 21,600
36 × 600 = 21,600
40 × 540 = 21,600
45 × 480 = 21,600
48 × 450 = 21,600
50 × 432 = 21,600
54 × 400 = 21,600
60 × 360 = 21,600
72 × 300 = 21,600
75 × 288 = 21,600
80 × 270 = 21,600
90 × 240 = 21,600
96 × 225 = 21,600
100 × 216 = 21,600
108 × 200 = 21,600
120 × 180 = 21,600
135 × 160 = 21,600
144 × 150 = 21,600
36 unique multiplications The final answer:
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