To find all the divisors of the number 138,888,890:
- 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 138,888,890:
The prime factorization of a number: finding the prime numbers that multiply together to make that number.
138,888,890 = 2 × 5 × 7 × 1092 × 167
138,888,890 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 = (1 + 1) × (1 + 1) × (1 + 1) × (2 + 1) × (1 + 1) = 2 × 2 × 2 × 3 × 2 = 48
But to actually calculate the factors, see below...
2. Multiply the prime factors of the number 138,888,890
- 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 =
5
prime factor =
7
composite factor = 2 × 5 =
10
composite factor = 2 × 7 =
14
composite factor = 5 × 7 =
35
composite factor = 2 × 5 × 7 =
70
prime factor =
109
prime factor =
167
composite factor = 2 × 109 =
218
composite factor = 2 × 167 =
334
composite factor = 5 × 109 =
545
composite factor = 7 × 109 =
763
composite factor = 5 × 167 =
835
composite factor = 2 × 5 × 109 =
1,090
composite factor = 7 × 167 =
1,169
composite factor = 2 × 7 × 109 =
1,526
composite factor = 2 × 5 × 167 =
1,670
composite factor = 2 × 7 × 167 =
2,338
composite factor = 5 × 7 × 109 =
3,815
composite factor = 5 × 7 × 167 =
5,845
composite factor = 2 × 5 × 7 × 109 =
7,630
composite factor = 2 × 5 × 7 × 167 =
11,690
This list continues below...
... This list continues from above
composite factor = 109
2 =
11,881
composite factor = 109 × 167 =
18,203
composite factor = 2 × 109
2 =
23,762
composite factor = 2 × 109 × 167 =
36,406
composite factor = 5 × 109
2 =
59,405
composite factor = 7 × 109
2 =
83,167
composite factor = 5 × 109 × 167 =
91,015
composite factor = 2 × 5 × 109
2 =
118,810
composite factor = 7 × 109 × 167 =
127,421
composite factor = 2 × 7 × 109
2 =
166,334
composite factor = 2 × 5 × 109 × 167 =
182,030
composite factor = 2 × 7 × 109 × 167 =
254,842
composite factor = 5 × 7 × 109
2 =
415,835
composite factor = 5 × 7 × 109 × 167 =
637,105
composite factor = 2 × 5 × 7 × 109
2 =
831,670
composite factor = 2 × 5 × 7 × 109 × 167 =
1,274,210
composite factor = 109
2 × 167 =
1,984,127
composite factor = 2 × 109
2 × 167 =
3,968,254
composite factor = 5 × 109
2 × 167 =
9,920,635
composite factor = 7 × 109
2 × 167 =
13,888,889
composite factor = 2 × 5 × 109
2 × 167 =
19,841,270
composite factor = 2 × 7 × 109
2 × 167 =
27,777,778
composite factor = 5 × 7 × 109
2 × 167 =
69,444,445
composite factor = 2 × 5 × 7 × 109
2 × 167 =
138,888,890
48 factors (divisors)
What times what is 138,888,890?
What number multiplied by what number equals 138,888,890?
All the combinations of any two natural numbers whose product equals 138,888,890.
1 × 138,888,890 = 138,888,890
2 × 69,444,445 = 138,888,890
5 × 27,777,778 = 138,888,890
7 × 19,841,270 = 138,888,890
10 × 13,888,889 = 138,888,890
14 × 9,920,635 = 138,888,890
35 × 3,968,254 = 138,888,890
70 × 1,984,127 = 138,888,890
109 × 1,274,210 = 138,888,890
167 × 831,670 = 138,888,890
218 × 637,105 = 138,888,890
334 × 415,835 = 138,888,890
545 × 254,842 = 138,888,890
763 × 182,030 = 138,888,890
835 × 166,334 = 138,888,890
1,090 × 127,421 = 138,888,890
1,169 × 118,810 = 138,888,890
1,526 × 91,015 = 138,888,890
1,670 × 83,167 = 138,888,890
2,338 × 59,405 = 138,888,890
3,815 × 36,406 = 138,888,890
5,845 × 23,762 = 138,888,890
7,630 × 18,203 = 138,888,890
11,690 × 11,881 = 138,888,890
24 unique multiplications The final answer:
(scroll down)