To find all the divisors of the number 61,440:
- 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 61,440:
The prime factorization of a number: finding the prime numbers that multiply together to make that number.
61,440 = 212 × 3 × 5
61,440 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 = (12 + 1) × (1 + 1) × (1 + 1) = 13 × 2 × 2 = 52
But to actually calculate the factors, see below...
2. Multiply the prime factors of the number 61,440
- 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
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
4 × 3 × 5 =
240
This list continues below...
... This list continues from above
composite factor = 2
8 =
256
composite factor = 2
6 × 5 =
320
composite factor = 2
7 × 3 =
384
composite factor = 2
5 × 3 × 5 =
480
composite factor = 2
9 =
512
composite factor = 2
7 × 5 =
640
composite factor = 2
8 × 3 =
768
composite factor = 2
6 × 3 × 5 =
960
composite factor = 2
10 =
1,024
composite factor = 2
8 × 5 =
1,280
composite factor = 2
9 × 3 =
1,536
composite factor = 2
7 × 3 × 5 =
1,920
composite factor = 2
11 =
2,048
composite factor = 2
9 × 5 =
2,560
composite factor = 2
10 × 3 =
3,072
composite factor = 2
8 × 3 × 5 =
3,840
composite factor = 2
12 =
4,096
composite factor = 2
10 × 5 =
5,120
composite factor = 2
11 × 3 =
6,144
composite factor = 2
9 × 3 × 5 =
7,680
composite factor = 2
11 × 5 =
10,240
composite factor = 2
12 × 3 =
12,288
composite factor = 2
10 × 3 × 5 =
15,360
composite factor = 2
12 × 5 =
20,480
composite factor = 2
11 × 3 × 5 =
30,720
composite factor = 2
12 × 3 × 5 =
61,440
52 factors (divisors)
What times what is 61,440?
What number multiplied by what number equals 61,440?
All the combinations of any two natural numbers whose product equals 61,440.
1 × 61,440 = 61,440
2 × 30,720 = 61,440
3 × 20,480 = 61,440
4 × 15,360 = 61,440
5 × 12,288 = 61,440
6 × 10,240 = 61,440
8 × 7,680 = 61,440
10 × 6,144 = 61,440
12 × 5,120 = 61,440
15 × 4,096 = 61,440
16 × 3,840 = 61,440
20 × 3,072 = 61,440
24 × 2,560 = 61,440
30 × 2,048 = 61,440
32 × 1,920 = 61,440
40 × 1,536 = 61,440
48 × 1,280 = 61,440
60 × 1,024 = 61,440
64 × 960 = 61,440
80 × 768 = 61,440
96 × 640 = 61,440
120 × 512 = 61,440
128 × 480 = 61,440
160 × 384 = 61,440
192 × 320 = 61,440
240 × 256 = 61,440
26 unique multiplications The final answer:
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