To find all the divisors of the number 213,920:
- 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 213,920:
The prime factorization of a number: finding the prime numbers that multiply together to make that number.
213,920 = 25 × 5 × 7 × 191
213,920 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 = (5 + 1) × (1 + 1) × (1 + 1) × (1 + 1) = 6 × 2 × 2 × 2 = 48
But to actually calculate the factors, see below...
2. Multiply the prime factors of the number 213,920
- 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
prime factor =
7
composite factor = 2
3 =
8
composite factor = 2 × 5 =
10
composite factor = 2 × 7 =
14
composite factor = 2
4 =
16
composite factor = 2
2 × 5 =
20
composite factor = 2
2 × 7 =
28
composite factor = 2
5 =
32
composite factor = 5 × 7 =
35
composite factor = 2
3 × 5 =
40
composite factor = 2
3 × 7 =
56
composite factor = 2 × 5 × 7 =
70
composite factor = 2
4 × 5 =
80
composite factor = 2
4 × 7 =
112
composite factor = 2
2 × 5 × 7 =
140
composite factor = 2
5 × 5 =
160
prime factor =
191
composite factor = 2
5 × 7 =
224
composite factor = 2
3 × 5 × 7 =
280
composite factor = 2 × 191 =
382
This list continues below...
... This list continues from above
composite factor = 2
4 × 5 × 7 =
560
composite factor = 2
2 × 191 =
764
composite factor = 5 × 191 =
955
composite factor = 2
5 × 5 × 7 =
1,120
composite factor = 7 × 191 =
1,337
composite factor = 2
3 × 191 =
1,528
composite factor = 2 × 5 × 191 =
1,910
composite factor = 2 × 7 × 191 =
2,674
composite factor = 2
4 × 191 =
3,056
composite factor = 2
2 × 5 × 191 =
3,820
composite factor = 2
2 × 7 × 191 =
5,348
composite factor = 2
5 × 191 =
6,112
composite factor = 5 × 7 × 191 =
6,685
composite factor = 2
3 × 5 × 191 =
7,640
composite factor = 2
3 × 7 × 191 =
10,696
composite factor = 2 × 5 × 7 × 191 =
13,370
composite factor = 2
4 × 5 × 191 =
15,280
composite factor = 2
4 × 7 × 191 =
21,392
composite factor = 2
2 × 5 × 7 × 191 =
26,740
composite factor = 2
5 × 5 × 191 =
30,560
composite factor = 2
5 × 7 × 191 =
42,784
composite factor = 2
3 × 5 × 7 × 191 =
53,480
composite factor = 2
4 × 5 × 7 × 191 =
106,960
composite factor = 2
5 × 5 × 7 × 191 =
213,920
48 factors (divisors)
What times what is 213,920?
What number multiplied by what number equals 213,920?
All the combinations of any two natural numbers whose product equals 213,920.
1 × 213,920 = 213,920
2 × 106,960 = 213,920
4 × 53,480 = 213,920
5 × 42,784 = 213,920
7 × 30,560 = 213,920
8 × 26,740 = 213,920
10 × 21,392 = 213,920
14 × 15,280 = 213,920
16 × 13,370 = 213,920
20 × 10,696 = 213,920
28 × 7,640 = 213,920
32 × 6,685 = 213,920
35 × 6,112 = 213,920
40 × 5,348 = 213,920
56 × 3,820 = 213,920
70 × 3,056 = 213,920
80 × 2,674 = 213,920
112 × 1,910 = 213,920
140 × 1,528 = 213,920
160 × 1,337 = 213,920
191 × 1,120 = 213,920
224 × 955 = 213,920
280 × 764 = 213,920
382 × 560 = 213,920
24 unique multiplications The final answer:
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