And why can BTC only reach a maximum of this value ? Any possible explanation ? I mean why this specific figure only ? That too with decimals ........
The number of bitcoins created in each block is already known. Beginning with block 6930000 around the year 2140, the number will forever be 0. Thus you can add up the numbers for all the blocks and you will compute a total of 20999999.97690000 BTC.