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Factoring and Multiples
Numbers

How do you factor a big number like 19800?

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Wiki User
May 12, 2012 6:41PM

The same as any other number. It will probably take a little longer since there's more factors. First step: Find the prime factorization.

23 x 32 x 52 x 11 = 19800 That gives you 2, 3, 5 and 11. Every other factor is in there in some combination. The rules of divisibility give you 4, 6, 8, 9 and 10. That gives you 10 factor pairs. (19800,1)(9900,2)(6600,3)(4950,4)(3960,5)(3300,6)(2475,8)(2200,9)(1980,10)(1800,11) Work your way up from there. 22 x 3, 3 x 5, 2 x 32, 22 x 5, 2 x 11, 23 x 3, 5 x 5, 2 x 3 x 5, 3 x 11, 22 x 32 (1650,12)(1320,15)(1100,18)(990,20)(900,22)(825,24)(792,25)(660,30)(600,33)(550,36) There are sixteen more. I bet you can find them. Stop at 132.