2^31 = 2 147 483 648‬ ... you need to divide the total number of atomic units by 10^N where N is number of decimals the coin use... Even if the coin uses more than 31-bit precision, it takes quite a long time to reach that many atomic units, because most of the new coins are mined or otherwise generated during first few years of coin's lifetime. Inflation does not have any correllated relation to emission as inflation is just how much the real value of the currency, coin or token drops during a single year.

For Steem, I think the current emission is about 346 million, and assuming N is 3, it would mean 346 billion out of 2 billion possible for 31-bit precision is already generated, which means Steem has to be using 63-bit precision instead. 1 bit of precision is always lost as it is required for handling negative numbers.