Overflowing of Unsigned Int

unsigned numbers can't overflow, but instead wrap around using the properties of modulo.

For instance, when unsigned int is 32 bits, the result would be: (a * b) mod 2^32.

As CharlesBailey pointed out, 253473829*13482018273 may use signed multiplication before being converted, and so you should be explicit about unsigned before the multiplication:

unsigned int someint = 253473829U * 13482018273U;

Unsigned integer overflow, unlike its signed counterpart, exhibits well-defined behaviour.

Values basically "wrap" around. It's safe and commonly used for counting down, or hashing/mod functions.