To find all the divisors of the number 138,460:
- 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 138,460:
The prime factorization of a number: finding the prime numbers that multiply together to make that number.
138,460 = 22 × 5 × 7 × 23 × 43
138,460 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 138,460
- 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 × 5 =
10
composite factor = 2 × 7 =
14
composite factor = 2
2 × 5 =
20
prime factor =
23
composite factor = 2
2 × 7 =
28
composite factor = 5 × 7 =
35
prime factor =
43
composite factor = 2 × 23 =
46
composite factor = 2 × 5 × 7 =
70
composite factor = 2 × 43 =
86
composite factor = 2
2 × 23 =
92
composite factor = 5 × 23 =
115
composite factor = 2
2 × 5 × 7 =
140
composite factor = 7 × 23 =
161
composite factor = 2
2 × 43 =
172
composite factor = 5 × 43 =
215
composite factor = 2 × 5 × 23 =
230
composite factor = 7 × 43 =
301
composite factor = 2 × 7 × 23 =
322
This list continues below...
... This list continues from above
composite factor = 2 × 5 × 43 =
430
composite factor = 2
2 × 5 × 23 =
460
composite factor = 2 × 7 × 43 =
602
composite factor = 2
2 × 7 × 23 =
644
composite factor = 5 × 7 × 23 =
805
composite factor = 2
2 × 5 × 43 =
860
composite factor = 23 × 43 =
989
composite factor = 2
2 × 7 × 43 =
1,204
composite factor = 5 × 7 × 43 =
1,505
composite factor = 2 × 5 × 7 × 23 =
1,610
composite factor = 2 × 23 × 43 =
1,978
composite factor = 2 × 5 × 7 × 43 =
3,010
composite factor = 2
2 × 5 × 7 × 23 =
3,220
composite factor = 2
2 × 23 × 43 =
3,956
composite factor = 5 × 23 × 43 =
4,945
composite factor = 2
2 × 5 × 7 × 43 =
6,020
composite factor = 7 × 23 × 43 =
6,923
composite factor = 2 × 5 × 23 × 43 =
9,890
composite factor = 2 × 7 × 23 × 43 =
13,846
composite factor = 2
2 × 5 × 23 × 43 =
19,780
composite factor = 2
2 × 7 × 23 × 43 =
27,692
composite factor = 5 × 7 × 23 × 43 =
34,615
composite factor = 2 × 5 × 7 × 23 × 43 =
69,230
composite factor = 2
2 × 5 × 7 × 23 × 43 =
138,460
48 factors (divisors)
What times what is 138,460?
What number multiplied by what number equals 138,460?
All the combinations of any two natural numbers whose product equals 138,460.
1 × 138,460 = 138,460
2 × 69,230 = 138,460
4 × 34,615 = 138,460
5 × 27,692 = 138,460
7 × 19,780 = 138,460
10 × 13,846 = 138,460
14 × 9,890 = 138,460
20 × 6,923 = 138,460
23 × 6,020 = 138,460
28 × 4,945 = 138,460
35 × 3,956 = 138,460
43 × 3,220 = 138,460
46 × 3,010 = 138,460
70 × 1,978 = 138,460
86 × 1,610 = 138,460
92 × 1,505 = 138,460
115 × 1,204 = 138,460
140 × 989 = 138,460
161 × 860 = 138,460
172 × 805 = 138,460
215 × 644 = 138,460
230 × 602 = 138,460
301 × 460 = 138,460
322 × 430 = 138,460
24 unique multiplications The final answer:
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