Adding multiple decimal places into a cell

I have a column with 10 digit numbers. I need to insert two decimal places into the number after the fourth and sixth digit. For example:
8523495000 -> 8523.49.5000
8443321020 -> 8443.32.1020
8523493000 -> 8523.49.3000

Does anyone have a formula that can help add these decimal places?

Try typing this in a column next to your values (say value 1 is in cell A1):

=left(A1,4)&"."&mid(A1,5,2)&"."&right(A1,4)

It'll be in a text format

If number is to be used as an identifier and not required to do math a custom format may suffice

Format would be 0000"."00"."0000 (CTRL+1 to enter formatting menu)

Thank you so much everyone. This was very helpful to solving my problem. I was attempting to format a series of 10 digit numbers with a preceding 0. For example, 0123456789 to 0123.45.67.89. I first used =TEXT (A1, "0000000000"). Then with your help I used function LEFT and created an additional MID.

=LEFT(C4,4)&"."&MID(C4,5,2)&"."&MID(C4,7,2)&"."&RIGHT(C4,2)


Sincerely,

Vangogh