public void CalculateFactorialDigitSum(BigInteger n)
{
BigInteger factorial = _factorialService.CalculateSeries(n);
string strFactorial = factorial.ToString();
BigInteger factorialSum = 0;
foreach (char item in strFactorial)
{
factorialSum = factorialSum + Convert.ToInt64(item.ToString());
}
Console.WriteLine(factorialSum);
}
