Full Idea
Russell's own stand was that numbers are really only sets of equivalent sets.
Gist of Idea
For Russell, numbers are sets of equivalent sets
Source
report of Bertrand Russell (Introduction to Mathematical Philosophy [1919]) by Paul Benacerraf - Logicism, Some Considerations (PhD) p.168
A Reaction
Benacerraf is launching a nice attack on this view, based on our inability to grasp huge numbers on this basis, or to see their natural order.