Insulin, a peptide hormone built from 51 amino acid residues, is one of the smallest proteins known (note that proteins are made up of chains of amino acids) with a molecular weight of 5808 Da. Twenty amino acids are encoded by the standard genetic code, that is, proteins are built from a basic set of 20 amino acids. How many possible proteins of length 51 can be made with 20 amino acids for each position in the protein?