[Python] Why is my computation so much faster in C# than Python

Below is a simple piece of process coded in C# and Python respectively (for those of you curious about the process, it's the solution for Problem No. 5 of Project Euler).

My question is, the C# code below takes only 9 seconds to iterate, while completion of Python code takes 283 seconds (to be exact, 283 seconds on Python 3.4.3 - 64 bits and 329 seconds on Python 2.7.9 - 32 bits).

So far, I've coded similar processes both in C# and Python and the execution time differences were comparable. This time however, there is an extreme difference between the elapsed times.

I think, some part of this difference arise from the flexible variable type of python language (I suspect, python converts some part of variables into double) but this much is still hard to explain.

What am I doing wrong?

My system: Windows-7 64 bits,

C# - VS Express 2012 (9 seconds)

Python 3.4.3 64 bits (283 seconds)

Python 2.7.9 32 bits (329 seconds)

c-sharp code:

using System;

namespace bug_vcs {
class Program {
public static void Main(string[] args) {
DateTime t0 = DateTime.Now;
int maxNumber = 20;
bool found = false;
long start = maxNumber;
while (!found) {
found = true;
int i = 2;
while ((i < maxNumber + 1) && found) {
if (start % i != 0) {
found = false;
}
i++;
}
start++;
}
Console.WriteLine("{0:d}", start - 1);
Console.WriteLine("time elapsed = {0:f} sec.", (DateTime.Now - t0).Seconds);
Console.ReadLine();
}
}
}


and python code:

from datetime import datetime

t0 = datetime.now()
max_number = 20
found = False
start = max_number
while not found:
found = True
i = 2
while ((i < max_number + 1) and found):
if (start % i) != 0:
found = False
i += 1
start += 1

print("number {0:d}\n".format(start - 1))

print("time elapsed = {0:f} sec.\n".format((datetime.now() - t0).seconds))

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