To find all the divisors of the number 42,780:
- 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 42,780:
The prime factorization of a number: finding the prime numbers that multiply together to make that number.
42,780 = 22 × 3 × 5 × 23 × 31
42,780 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 = (2 + 1) × (1 + 1) × (1 + 1) × (1 + 1) × (1 + 1) = 3 × 2 × 2 × 2 × 2 = 48
But to actually calculate the factors, see below...
2. Multiply the prime factors of the number 42,780
- 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 × 5 =
10
composite factor = 2
2 × 3 =
12
composite factor = 3 × 5 =
15
composite factor = 2
2 × 5 =
20
prime factor =
23
composite factor = 2 × 3 × 5 =
30
prime factor =
31
composite factor = 2 × 23 =
46
composite factor = 2
2 × 3 × 5 =
60
composite factor = 2 × 31 =
62
composite factor = 3 × 23 =
69
composite factor = 2
2 × 23 =
92
composite factor = 3 × 31 =
93
composite factor = 5 × 23 =
115
composite factor = 2
2 × 31 =
124
composite factor = 2 × 3 × 23 =
138
composite factor = 5 × 31 =
155
composite factor = 2 × 3 × 31 =
186
This list continues below...
... This list continues from above
composite factor = 2 × 5 × 23 =
230
composite factor = 2
2 × 3 × 23 =
276
composite factor = 2 × 5 × 31 =
310
composite factor = 3 × 5 × 23 =
345
composite factor = 2
2 × 3 × 31 =
372
composite factor = 2
2 × 5 × 23 =
460
composite factor = 3 × 5 × 31 =
465
composite factor = 2
2 × 5 × 31 =
620
composite factor = 2 × 3 × 5 × 23 =
690
composite factor = 23 × 31 =
713
composite factor = 2 × 3 × 5 × 31 =
930
composite factor = 2
2 × 3 × 5 × 23 =
1,380
composite factor = 2 × 23 × 31 =
1,426
composite factor = 2
2 × 3 × 5 × 31 =
1,860
composite factor = 3 × 23 × 31 =
2,139
composite factor = 2
2 × 23 × 31 =
2,852
composite factor = 5 × 23 × 31 =
3,565
composite factor = 2 × 3 × 23 × 31 =
4,278
composite factor = 2 × 5 × 23 × 31 =
7,130
composite factor = 2
2 × 3 × 23 × 31 =
8,556
composite factor = 3 × 5 × 23 × 31 =
10,695
composite factor = 2
2 × 5 × 23 × 31 =
14,260
composite factor = 2 × 3 × 5 × 23 × 31 =
21,390
composite factor = 2
2 × 3 × 5 × 23 × 31 =
42,780
48 factors (divisors)
What times what is 42,780?
What number multiplied by what number equals 42,780?
All the combinations of any two natural numbers whose product equals 42,780.
1 × 42,780 = 42,780
2 × 21,390 = 42,780
3 × 14,260 = 42,780
4 × 10,695 = 42,780
5 × 8,556 = 42,780
6 × 7,130 = 42,780
10 × 4,278 = 42,780
12 × 3,565 = 42,780
15 × 2,852 = 42,780
20 × 2,139 = 42,780
23 × 1,860 = 42,780
30 × 1,426 = 42,780
31 × 1,380 = 42,780
46 × 930 = 42,780
60 × 713 = 42,780
62 × 690 = 42,780
69 × 620 = 42,780
92 × 465 = 42,780
93 × 460 = 42,780
115 × 372 = 42,780
124 × 345 = 42,780
138 × 310 = 42,780
155 × 276 = 42,780
186 × 230 = 42,780
24 unique multiplications The final answer:
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