Thanks for the tip. I've never heard about Electroneum before until now, but it seems like an interesting cryptocurrency to start mining with my phone. If it's airdrop mining, then I guess that there's no actual hashpower being used from the device's CPU. This is clever, IMO, as it prevents battery drainage and reduction of the lifespan of the device itself, making it easier and accessible for anyone to earn free coins in their spare time.

While ETN has been added to my list of coins to mine with a smartphone, I'm on the hunt for other cryptocurrencies that are extremely easy to mine with either a smartphone or tablet. aeternity is one of those coins I can't wait for it to launch, as its unique Cuckoo Cycle PoW algorithm, allows any device to easily mine coins without effort. This would allow greater decentralization over the cryptocurrency, as it allows anyone to participate in the security of the same (unlike Bitcoin and other popular cryptos).

Another cryptocurrency which I've found out to be easy to mine with a smartphone is called Magi (XMG). This one is based on M7M PoW algorithm which goes easy on any device, since it has a model where the higher the hashrate in the network is, the lower the reward, allowing small miners to participate in the process. However, while this coin is easy to mine with a mobile device, it's not quite profitable after all. Perhaps, none of the CPU mineable coins are profitable, but if it makes you free money in your spare time, then it shouldn't matter.