EditText width not taking effect Android

I have the following XML code:

<EditText
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:inputType="numberDecimal"
    android:id="@+id/et1"
    android:autoText="false"
    android:text="40"
    android:layout_centerVertical="true"
    android:layout_toRightOf="@+id/radioGroup"
    android:width="20dp"
    android:layout_toStartOf="@+id/radioGroup2"
    android:layout_alignRight="@+id/textView"
    android:layout_alignEnd="@+id/textView" />

I would like to set a specific width or a max width would also do the trick (not working either). The text field is going from the vertical centre to the far right and I would like it to position from vertical centre to 20p to the right. When I set max_width or width it doesn't seem to take any effect. It makes no difference what I put in.

Any idea why? Thanks for an answers.