For something that's been with me my entire life, I've never really noticed whether or not it's "heavy". It just "is".
Sometimes when I'm hard, I can swing my hips and it whips back and forth with quite a bit of inertia, but don't know (nor do I really care that much) whether or not it's because of size or weight.
And since it'd have to be removed in order to weigh it, I'll leave that up to the coroner / medical examiner to do once I'm dead. After all, I've elected to be an organ donor and to donate my body to science when I'm dead so let some others answer that question.