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F12, that is the twelfth Fermat number, or 2^(2^12)+1 is equal to 24096+1.
In decimal, the number has one thousand two hundred and thirty-four digits. Such a number is impossible to completely factorise (for comparison, the number F9(10) or 10512+1 is still not completely factored), but we do know six prime factors of F12 and that the cofactor is composite.
This means F12 must have at least eight distinct prime factors, as compared to no more than five for F11, four for F10, three for F9 and two for F8, F7, F6 and F5.
The known prime factors of F12 are:
- 114689, the second smallest Fermat divisor and was discovered in 1877 well before computers by Edouard Lucas
- 26017793 and
- 63766529, both discovered in 1903 by Western
- 190274191361, discovered in 1974
- 1256132134125569, discovered in July 1986, and
- 568630647535356955169033410940867804839360742060818433, discovered in March 2010
Before the sixth factor of F12 was found it was known after extensive use of the Elliptic Curve Method that there could be no factor of the 1,187 digit composite factor of F12 with under 45 digits.
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What is the greatest common factor of 12 24 and 132?
12 is a factor of all of them. Since 12 can't have a factor higher than 12, it must be the GCF.
What is the greatest common factor for 12 and 60?
The Greatest Common Factor of 12, 60 is 12.
Why is 24 not a factor of 12?
That simply means that there is no integer solution to:24n = 12 For comparison, 4 IS a factor; so the equation: 4n = 12 DOES have an integer solution.
What is the greatest factor of 12 and 20?
The greatest common factor of 12 and 20 is 4
What is a repeating factor?
A square root
What is the greatest factor of 12?
The greatest factor of 12 is 12.
Why is 12 not a factor?
12 can be a factor. It's a factor of 24, for example.
Is 12 a factor of 41?
No, 12 is not a factor of 41.
What is the greatest factor in three and 12?
The greatest factor is 12 which is a factor of 12, though not of 3.
Is 2 a factor or a product of 12?
2 is a factor of 12.
Is 12 a prime factor?
12 is a composite number, not a prime factor.
What is the greatest common factor of 12 24 and 132?
12 is a factor of all of them. Since 12 can't have a factor higher than 12, it must be the GCF.
Which is not a common factor of 12 and 30 2356?
5 is not a factor of 12.
Is 12 a factor of 4?
No, 12 is a multiple of 4. 4 is a factor of 12.
What is the greatest common factor for 12 and 60?
The Greatest Common Factor of 12, 60 is 12.
What is an odd number between 520 and 530 with 12 as one of its factor?
An odd number can't have 12 as a factor. 528 does have 12 as a factor.
Is 12 a factor number or a multiple number?
Either or both. 12 is a factor of 24. 12 is a multiple of 6. 12 is both a factor and a multiple of itself.
