BitCoin system has 21 million BitCoin tokens.
Each token has 10⁸ decimal places, with the 10^-8 slot being named “satoshis”. The smallest possible unit in the BitCoin system is 1 satoshi, or 0.0000001 BitCoins.
This is akin to how we have Dollars (BitCoin) and cents (satoshis), but with 8 decimal places rather than 2 (in the USD).
10⁸ decimal places, means 100 million satoshis = 1 BitCoin.
BitCoin has 16 possible integer places. 8 in front of the decimal (21mm) and 8 to the right (.0000001, a satoshi).