To find all the divisors of the number 642,000:
- 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 642,000:
The prime factorization of a number: finding the prime numbers that multiply together to make that number.
642,000 = 24 × 3 × 53 × 107
642,000 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 = (4 + 1) × (1 + 1) × (3 + 1) × (1 + 1) = 5 × 2 × 4 × 2 = 80
But to actually calculate the factors, see below...
2. Multiply the prime factors of the number 642,000
- 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 = 5
2 =
25
composite factor = 2 × 3 × 5 =
30
composite factor = 2
3 × 5 =
40
composite factor = 2
4 × 3 =
48
composite factor = 2 × 5
2 =
50
composite factor = 2
2 × 3 × 5 =
60
composite factor = 3 × 5
2 =
75
composite factor = 2
4 × 5 =
80
composite factor = 2
2 × 5
2 =
100
prime factor =
107
composite factor = 2
3 × 3 × 5 =
120
composite factor = 5
3 =
125
composite factor = 2 × 3 × 5
2 =
150
composite factor = 2
3 × 5
2 =
200
composite factor = 2 × 107 =
214
composite factor = 2
4 × 3 × 5 =
240
composite factor = 2 × 5
3 =
250
composite factor = 2
2 × 3 × 5
2 =
300
composite factor = 3 × 107 =
321
composite factor = 3 × 5
3 =
375
composite factor = 2
4 × 5
2 =
400
composite factor = 2
2 × 107 =
428
composite factor = 2
2 × 5
3 =
500
composite factor = 5 × 107 =
535
composite factor = 2
3 × 3 × 5
2 =
600
composite factor = 2 × 3 × 107 =
642
composite factor = 2 × 3 × 5
3 =
750
This list continues below...
... This list continues from above
composite factor = 2
3 × 107 =
856
composite factor = 2
3 × 5
3 =
1,000
composite factor = 2 × 5 × 107 =
1,070
composite factor = 2
4 × 3 × 5
2 =
1,200
composite factor = 2
2 × 3 × 107 =
1,284
composite factor = 2
2 × 3 × 5
3 =
1,500
composite factor = 3 × 5 × 107 =
1,605
composite factor = 2
4 × 107 =
1,712
composite factor = 2
4 × 5
3 =
2,000
composite factor = 2
2 × 5 × 107 =
2,140
composite factor = 2
3 × 3 × 107 =
2,568
composite factor = 5
2 × 107 =
2,675
composite factor = 2
3 × 3 × 5
3 =
3,000
composite factor = 2 × 3 × 5 × 107 =
3,210
composite factor = 2
3 × 5 × 107 =
4,280
composite factor = 2
4 × 3 × 107 =
5,136
composite factor = 2 × 5
2 × 107 =
5,350
composite factor = 2
4 × 3 × 5
3 =
6,000
composite factor = 2
2 × 3 × 5 × 107 =
6,420
composite factor = 3 × 5
2 × 107 =
8,025
composite factor = 2
4 × 5 × 107 =
8,560
composite factor = 2
2 × 5
2 × 107 =
10,700
composite factor = 2
3 × 3 × 5 × 107 =
12,840
composite factor = 5
3 × 107 =
13,375
composite factor = 2 × 3 × 5
2 × 107 =
16,050
composite factor = 2
3 × 5
2 × 107 =
21,400
composite factor = 2
4 × 3 × 5 × 107 =
25,680
composite factor = 2 × 5
3 × 107 =
26,750
composite factor = 2
2 × 3 × 5
2 × 107 =
32,100
composite factor = 3 × 5
3 × 107 =
40,125
composite factor = 2
4 × 5
2 × 107 =
42,800
composite factor = 2
2 × 5
3 × 107 =
53,500
composite factor = 2
3 × 3 × 5
2 × 107 =
64,200
composite factor = 2 × 3 × 5
3 × 107 =
80,250
composite factor = 2
3 × 5
3 × 107 =
107,000
composite factor = 2
4 × 3 × 5
2 × 107 =
128,400
composite factor = 2
2 × 3 × 5
3 × 107 =
160,500
composite factor = 2
4 × 5
3 × 107 =
214,000
composite factor = 2
3 × 3 × 5
3 × 107 =
321,000
composite factor = 2
4 × 3 × 5
3 × 107 =
642,000
80 factors (divisors)
What times what is 642,000?
What number multiplied by what number equals 642,000?
All the combinations of any two natural numbers whose product equals 642,000.
1 × 642,000 = 642,000
2 × 321,000 = 642,000
3 × 214,000 = 642,000
4 × 160,500 = 642,000
5 × 128,400 = 642,000
6 × 107,000 = 642,000
8 × 80,250 = 642,000
10 × 64,200 = 642,000
12 × 53,500 = 642,000
15 × 42,800 = 642,000
16 × 40,125 = 642,000
20 × 32,100 = 642,000
24 × 26,750 = 642,000
25 × 25,680 = 642,000
30 × 21,400 = 642,000
40 × 16,050 = 642,000
48 × 13,375 = 642,000
50 × 12,840 = 642,000
60 × 10,700 = 642,000
75 × 8,560 = 642,000
80 × 8,025 = 642,000
100 × 6,420 = 642,000
107 × 6,000 = 642,000
120 × 5,350 = 642,000
125 × 5,136 = 642,000
150 × 4,280 = 642,000
200 × 3,210 = 642,000
214 × 3,000 = 642,000
240 × 2,675 = 642,000
250 × 2,568 = 642,000
300 × 2,140 = 642,000
321 × 2,000 = 642,000
375 × 1,712 = 642,000
400 × 1,605 = 642,000
428 × 1,500 = 642,000
500 × 1,284 = 642,000
535 × 1,200 = 642,000
600 × 1,070 = 642,000
642 × 1,000 = 642,000
750 × 856 = 642,000
40 unique multiplications The final answer:
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