There will be 21.4 million Zcoins. Zcoin follows the same halving cycle as Bitcoin (every 4 years).
It was originally planned that 20% of Zcoins (10 XZC per block) in the first 4 years will be distributed to the Founders’ Reward which is equivalent to 10% of total supply. The Founders’ Reward consists of Poramin Insom (lead dev and Founder) (4%), seed investors (12%) and the team wallet (4%).
However upon the launch of Znodes, the Founders and the team have agreed to reduce this to 14% of the block reward: 2% Poramin Insom, seed investors (6%) and team wallet (6%).
To find out how the Founder’s Rewards are used, see here.
After the first 4 years, the block reward goes completely towards the miners and Znode rewards.