The total number of electoral votes isn't fixed, and in fact has changed dramatically over the years. Additionally, the number of electors (electoral votes) per state is determined by the Census. "A state's number of electors equals the number of representatives plus two electors for the senators the state has in the United States Congress."

You can see a table of the number of electors per state, and how that changed over time, here: https://en.wikipedia.org/wiki/United_States_Electoral_Colleg....