More has been claimed about Mary Magdalene on less evidence than about almost any figure in the New Testament, and the central claim can be dated to a specific sermon.
What the Gospels say is brief and consistent. She is from Magdala on the Sea of Galilee. Luke says Jesus cast seven demons out of her and that she was among the women who supported the movement out of their own means, which indicates independent resources. All four Gospels place her at the crucifixion, all four place her at the tomb, and in each she is among the first to find it empty. In John she is alone at the tomb, mistakes the risen Jesus for the gardener, and is sent to tell the others, which is the basis of the ancient Western title apostle to the apostles, used of her by Hippolytus in the third century and by others after.
She is never called a prostitute. She is never called a sinner. Nothing connects her to sexual sin of any kind.
The unnamed woman of Luke 7 who anoints Jesus' feet and is described as a sinner is a different person in a different chapter. Mary of Bethany, sister of Martha and Lazarus, who anoints Jesus in John 12, is a third. In 591, Gregory the Great preached a homily that fused all three into one woman, read the seven demons as the seven deadly sins, and identified the sin as unchastity. That identification held in the Western church for fourteen centuries. The Eastern churches never adopted it and always kept the three women distinct.