The alpha satoshi corresponds to the first satoshi of a bitcoin. There are as many as there are bitcoins : 21 million.

For the first four years of Bitcoin’s existence, before the first halving, the validation of each block remunerated miners with the production of 50 bitcoins. Block 78 therefore saw the production of 50 bitcoins – and 50 satoshis alphas.

Removing the last eight zeros from the satoshis number gives you the bitcoin number.