System.Math provides the BigMul method for cases where you have to find the product of two large integer numerals that may result in a value that would cause an System.Overflow Exception. The BigMul method returns a long number, which avoids the overflow.
System.Int32 i = 245525352;
System.Int32 j = 245552352;
System.Int32 k = 0;
//This one will work
var result = System.Math.BigMul(i, j);
//This one will throw Arithmetic overflow exception
k = i * j;