To find all the divisors of the number 25,245:
- 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 25,245:
The prime factorization of a number: finding the prime numbers that multiply together to make that number.
25,245 = 33 × 5 × 11 × 17
25,245 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 = (3 + 1) × (1 + 1) × (1 + 1) × (1 + 1) = 4 × 2 × 2 × 2 = 32
But to actually calculate the factors, see below...
2. Multiply the prime factors of the number 25,245
- 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 =
3
prime factor =
5
composite factor = 3
2 =
9
prime factor =
11
composite factor = 3 × 5 =
15
prime factor =
17
composite factor = 3
3 =
27
composite factor = 3 × 11 =
33
composite factor = 3
2 × 5 =
45
composite factor = 3 × 17 =
51
composite factor = 5 × 11 =
55
composite factor = 5 × 17 =
85
composite factor = 3
2 × 11 =
99
composite factor = 3
3 × 5 =
135
composite factor = 3
2 × 17 =
153
This list continues below...
... This list continues from above
composite factor = 3 × 5 × 11 =
165
composite factor = 11 × 17 =
187
composite factor = 3 × 5 × 17 =
255
composite factor = 3
3 × 11 =
297
composite factor = 3
3 × 17 =
459
composite factor = 3
2 × 5 × 11 =
495
composite factor = 3 × 11 × 17 =
561
composite factor = 3
2 × 5 × 17 =
765
composite factor = 5 × 11 × 17 =
935
composite factor = 3
3 × 5 × 11 =
1,485
composite factor = 3
2 × 11 × 17 =
1,683
composite factor = 3
3 × 5 × 17 =
2,295
composite factor = 3 × 5 × 11 × 17 =
2,805
composite factor = 3
3 × 11 × 17 =
5,049
composite factor = 3
2 × 5 × 11 × 17 =
8,415
composite factor = 3
3 × 5 × 11 × 17 =
25,245
32 factors (divisors)
What times what is 25,245?
What number multiplied by what number equals 25,245?
All the combinations of any two natural numbers whose product equals 25,245.
1 × 25,245 = 25,245
3 × 8,415 = 25,245
5 × 5,049 = 25,245
9 × 2,805 = 25,245
11 × 2,295 = 25,245
15 × 1,683 = 25,245
17 × 1,485 = 25,245
27 × 935 = 25,245
33 × 765 = 25,245
45 × 561 = 25,245
51 × 495 = 25,245
55 × 459 = 25,245
85 × 297 = 25,245
99 × 255 = 25,245
135 × 187 = 25,245
153 × 165 = 25,245
16 unique multiplications The final answer:
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