Primecoin is a cryptocurrency based on finding prime numbers. Identifying prime numbers plays a central role in cryptography. Primecoin's unique Proof-of-Work (PoW) consensus mechanism is able to increase transaction speeds and improve energy efficiency.
The network searches for special prime number chains known as Cunningham chains and bi-twin chains, which are of interest in mathematical research.

BitKan is a Chinese cryptocurrency site and trading platform with a strong following. Their Ethereum-based KAN token facilitates community cooperation among the site's followers.

TransferCoin is a digital currency with a hybrid PoW and PoS consensus mechanism. TransferCoin uses the X11 encryption algorithm and has a relatively fast block time.