There are a lot of Bitcoin explorers, but a Bitcoin explorer will usually show the last blocks, the details of a transaction and the details/translations of an address.
What you are asking for are statistics most explorers don't show.

The Circulating Supply is shown by coinmarketcap.
I'll look a bit, maybe I find some of the other data too, but I don't promise results.

Edit: I think that the number of nodes is next to impossible to find out, since one node sees only its peers and I think that no other reporting/cross check is done, possibly even for privacy.