There are real some real similarities though, like other crucified saviors, miracle workers, virgin births, things like that. I remember once receiving a phone call from an older woman who I knew well, whose parish priest had actually used these kinds of similarities to teach that the Bible is pretty much made up. She was very unnerved. The answer is that when Jesus came on earth, He wished to reach all people with the good news of salvation. Therefore, He fulfilled the expectations of their cultures for what a god should be.
You can turn this idea either way. Those who wish to doubt the truth of Jesus as the Messiah can claim that Christianity copies paganism. Those who wish to believe Jesus truly is the Messiah can simply point out that in their longing for a true Messiah, pagans realized some of the things Jesus would be when He came, and not knowing the truth as it was known to the Jews, they gave these properties to their own gods.
And let's remember, most of what Jesus would be and do was prophesied by Isaiah, etc. hundreds of years earlier. Some was even prophesied implicitly in the garden. So the pagan religions had a head start on what to copy.