How to determine the number of common factors?

[Guest]

Does anyone have any suggestions on how to determine the number of common
factors based on given number? For example,
10 is given in cell A1, then the common factors for 10 are 1,2,5,10. There
are 4 numbers for common factors, then I will return 4 in cell B1.
I will try different number in cell A1,
Does anyone have any suggestions on how to determine the number of common
factors in cell B2?
Thanks in advance for any suggestions
Eric

 

[Guest]

Use the function below. Call with

=NumberFactors(10)

Function NumberFactors(target)

'include target
'then you only need to check 1/2 the numbers
NumberFactors = 1
For i = 1 To target / 2
If target Mod i = 0 Then
NumberFactors = NumberFactors + 1
End If
Next i

End Function

 

[T. Valko]

Try this:

=SUMPRODUCT(--(MOD(A1,ROW(INDIRECT("1:"&A1)))=0))

Works only with integers. If the number is 0 you'll get an error. If it's
possible that the number can be 0 then use this version:

=IF(AND(ISNUMBER(A1),A1=0),1,SUMPRODUCT(--(MOD(A1,ROW(INDIRECT("1:"&A1)))=0)))

 

[T. Valko]

Improvement:

This takes care of 0 in a different way and accounts for an empty cell:

=IF(A1="","",SUMPRODUCT(--(MOD(A1,ROW(INDIRECT("1:"&MAX(1,A1))))=0)))