Senators each Democratic President had when taking office:
FDR: 58 (of 96)
Truman: 57 (of 96)
Kennedy: 64
LBJ: 66
Carter: 61
Clinton: 57
Obama: 58
Biden: 50
Every Dem President of the last 100 years got at least 57 Dem Senators to start with. Except Biden who only got 50.