2120297919943148946411837205892771504128704971219136 is greater than the total number of reachable positions in chess in which pawns are always in rows 2-7 and a non-fixed initial position has at most 32 pieces and is almost arbitrary

Abstract

A short MuPAD program shows that 2120297919943148946411837205892771504128704971219136 is greater than the total number of reachable positions in chess in which pawns are always in rows 2-7 and a non-fixed initial position has at most 32 pieces and is almost arbitrary i.e. both kings are always on the chessboard and not adjacent, White begins the game, and if black king is in check then White cannot have a move.