Is there a formula or way to calculate which numbers we can divide a certain number to only produce non decimal numbers?

ak730

New member
Joined
Nov 20, 2023
Messages
1
Hi,

Not sure if Im explaining correctly.

Is there a formula or way to calculate which numbers we can divide a certain number to only produce non decimal numbers?

For example:
466

Only 2 and 233 will produce a non decimal number.
 

topsquark

Senior Member
Joined
Aug 27, 2012
Messages
2,253
Hi,

Not sure if Im explaining correctly.

Is there a formula or way to calculate which numbers we can divide a certain number to only produce non decimal numbers?

For example:
466

Only 2 and 233 will produce a non decimal number.
Yes, it's called "prime factorization":
[imath]466 = 2 \cdot 233[/imath]

So 466 can only be divided "evenly" by the primes 2 and 233 (ie. without any extra decimals.)

A more illuminating example would be [imath]180 = 2^2 \cdot 3^2 \cdot 5[/imath]. 180 can be divided evenly by any combination of two 2's, two 3's and a 5:
[imath]2, 3, 2^2, 5, 2 \cdot 3, 3^2, 2 \cdot 5, 2^2 \cdot 3, 3 \cdot 5, 2 \cdot 3^2, 2^2 \cdot 5, 2 \cdot 3 \cdot 5, 2^2 \cdot 3^2, 3^2 \cdot 5, 2 \cdot 3^2 \cdot 5, 2^2 \cdot 3^2 \cdot 5[/imath]

or 2, 3, 4, 5, 6, 9, 10, 12, 15, 18, 20, 30, 36, 45, 60, 90, 180.

-Dan
 

Dr.Peterson

Elite Member
Joined
Nov 12, 2017
Messages
15,607
Hi,

Not sure if Im explaining correctly.

Is there a formula or way to calculate which numbers we can divide a certain number to only produce non decimal numbers?

For example:
466

Only 2 and 233 will produce a non decimal number.
What you're asking for is the "factors" of 466. These are its divisors, numbers that evenly divide it, producing an integer.

There is no simple "formula", but once you have found the prime factors (which can take some time), @topsquark's suggestion finds all factors by an orderly process. Can you see what that process is?

Now that you have words for what you want, you should be able to search for fuller explanations of these ideas.
 

pka

Elite Member
Joined
Jan 29, 2005
Messages
11,963
Not sure if Im explaining correctly.Is there a formula or way to calculate which numbers we can divide a certain number to only produce non decimal numbers?
For example: 466 Only 2 and 233 will produce a non decimal number.
The easiest way to answer is by way of example.
Step one is to find the prime factors. [imath]19,132,858,800=2^4*3^3*5^2*11^6[/imath]
Step two is to list each exponent plus one: [imath](4+1),(3+1),(2+1),(6+1)[/imath]
Step three find the product of those: [imath](5)\cdot(4)\cdot(3)\cdot(7)=420[/imath]
That tell us that there are [imath]420[/imath] positive integral factors of [imath]19,132,858,800[/imath]
If you work out why that works you will understand your own question.
[imath][/imath][imath][/imath]
 

Steven G

Elite Member
Joined
Dec 30, 2014
Messages
14,244
Hi,

Not sure if Im explaining correctly.

Is there a formula or way to calculate which numbers we can divide a certain number to only produce non decimal numbers?

For example:
466

Only 2 and 233 will produce a non decimal number.
For the record 466/1 and 466/466 will also be non decimal numbers.
 

khansaheb

Full Member
Joined
Apr 6, 2023
Messages
481
For the record 466/1 and 466/466 will also be non decimal numbers.
466/1 = 466.0000000

466/466 = 1.0000000

I think there is a confusion about the definition of "non-decimal number". A better classification would be non-recurring decimal - as in π) or recurring decimal (as in 4/33 = 0.121212...)
 
Last edited:
Top