Big number in C++

Question

I am trying to place a big number in a C++ variable. The number is 600851475143

I tried unsigned long long int but got an error saying it the constant was too big.

Answer 1

The number is 600851475143 isn't too large for a long long int but you need to use the LL suffix when using a long long constants (ULL for unsigned long long int):

unsigned long long int num = 600851475143ULL;