Random() Maximum

There is still a problem:
over the serial i get only values until 5 digits.
for evaluation i used this code:

long x;
void setup(){
Serial.begin(9600);
}
void loop(){
x=random(1576800000L);
Serial.println (x);
delay(100);
}

it returns values until 32 thousand something.
i dont need the serial thing, but i want to be shure if the random numbers are
created throughout the entire range.
is it just a serial problem?

w