Correct. 55 rows would be 5661.
It's easy to see this, Bubikol, if you do
SELECT COUNT(*), SUM(111) FROM xtable
What you are telling SQL (any SQL, not just MySQL) to do is to add 111 to the sum for each row in the table.
Think about it: If you do
SELECT SUM(someField) FROM xtable
all that tells SQL to do is to add the value of field someField
to the sum for each row in the table. So when you use a constant, instead, it is the constant that gets added for each row.
Nothing "random" about it.