To find all the divisors of the number 20,789,780:
- 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 20,789,780:
The prime factorization of a number: finding the prime numbers that multiply together to make that number.
20,789,780 = 22 × 5 × 11 × 53 × 1,783
20,789,780 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 20,789,780
- 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
composite factor = 2
2 =
4
prime factor =
5
composite factor = 2 × 5 =
10
prime factor =
11
composite factor = 2
2 × 5 =
20
composite factor = 2 × 11 =
22
composite factor = 2
2 × 11 =
44
prime factor =
53
composite factor = 5 × 11 =
55
composite factor = 2 × 53 =
106
composite factor = 2 × 5 × 11 =
110
composite factor = 2
2 × 53 =
212
composite factor = 2
2 × 5 × 11 =
220
composite factor = 5 × 53 =
265
composite factor = 2 × 5 × 53 =
530
composite factor = 11 × 53 =
583
composite factor = 2
2 × 5 × 53 =
1,060
composite factor = 2 × 11 × 53 =
1,166
prime factor =
1,783
composite factor = 2
2 × 11 × 53 =
2,332
composite factor = 5 × 11 × 53 =
2,915
composite factor = 2 × 1,783 =
3,566
This list continues below...
... This list continues from above
composite factor = 2 × 5 × 11 × 53 =
5,830
composite factor = 2
2 × 1,783 =
7,132
composite factor = 5 × 1,783 =
8,915
composite factor = 2
2 × 5 × 11 × 53 =
11,660
composite factor = 2 × 5 × 1,783 =
17,830
composite factor = 11 × 1,783 =
19,613
composite factor = 2
2 × 5 × 1,783 =
35,660
composite factor = 2 × 11 × 1,783 =
39,226
composite factor = 2
2 × 11 × 1,783 =
78,452
composite factor = 53 × 1,783 =
94,499
composite factor = 5 × 11 × 1,783 =
98,065
composite factor = 2 × 53 × 1,783 =
188,998
composite factor = 2 × 5 × 11 × 1,783 =
196,130
composite factor = 2
2 × 53 × 1,783 =
377,996
composite factor = 2
2 × 5 × 11 × 1,783 =
392,260
composite factor = 5 × 53 × 1,783 =
472,495
composite factor = 2 × 5 × 53 × 1,783 =
944,990
composite factor = 11 × 53 × 1,783 =
1,039,489
composite factor = 2
2 × 5 × 53 × 1,783 =
1,889,980
composite factor = 2 × 11 × 53 × 1,783 =
2,078,978
composite factor = 2
2 × 11 × 53 × 1,783 =
4,157,956
composite factor = 5 × 11 × 53 × 1,783 =
5,197,445
composite factor = 2 × 5 × 11 × 53 × 1,783 =
10,394,890
composite factor = 2
2 × 5 × 11 × 53 × 1,783 =
20,789,780
48 factors (divisors)
What times what is 20,789,780?
What number multiplied by what number equals 20,789,780?
All the combinations of any two natural numbers whose product equals 20,789,780.
1 × 20,789,780 = 20,789,780
2 × 10,394,890 = 20,789,780
4 × 5,197,445 = 20,789,780
5 × 4,157,956 = 20,789,780
10 × 2,078,978 = 20,789,780
11 × 1,889,980 = 20,789,780
20 × 1,039,489 = 20,789,780
22 × 944,990 = 20,789,780
44 × 472,495 = 20,789,780
53 × 392,260 = 20,789,780
55 × 377,996 = 20,789,780
106 × 196,130 = 20,789,780
110 × 188,998 = 20,789,780
212 × 98,065 = 20,789,780
220 × 94,499 = 20,789,780
265 × 78,452 = 20,789,780
530 × 39,226 = 20,789,780
583 × 35,660 = 20,789,780
1,060 × 19,613 = 20,789,780
1,166 × 17,830 = 20,789,780
1,783 × 11,660 = 20,789,780
2,332 × 8,915 = 20,789,780
2,915 × 7,132 = 20,789,780
3,566 × 5,830 = 20,789,780
24 unique multiplications The final answer:
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