What is the number of transactions per second?
Transactions per second are not a very good measure of scalability due to several factors (internet latency, capabilities of different nodes, etc).
But an example of 1000 transactions in a single block (~7 seconds) is given here: https://nyzo.co/blockPlain/1772324
Transaction rates of up to 3500/block (500 TPS) have been demonstrated on mainnet. The actual transaction rate depends on in cycle verifier specs, which is expected to improve over time.