It's easy to forget, even if you know intellectually, that for Jonathan Harker, as for the first readers of the novel, the name "Dracula" holds no special terror. It's just this guy's name.
The cultural influence of Dracula is so strong that even his title "Count" feels kind of sinister to a lot of English speakers. Sesame Street may have helped cement that association, to be honest. But for the characters in the novel there's nothing inherently suspect or creepy about a guy being a Count. It makes him LESS suspicious if anything.
At first.
But actually one of the reasons we colloquially associate Count with Dracula so strongly is that there aren't Counts in England, there are Dukes, Earls, Marquesses, Viscounts, and Barons. So to an English audience "Count" doesn't just signify aristocracy it signifies foreignness. If Dracula was English he would be Earl Dracula, and by convention everyone would probably just call him "Lord Dracula".
And since he's not English he's Count, and we can call him "the Count" in the novel with no confusion, although calling him "the Earl" would presumably be confusing for the characters even if it wasn't confusing for the readers. They probably know other Earls.
There's an emphasis on this point, because one of the other characters is Lord Godalming. Is Lord Godalming a Duke, a Marquess, an Earl, a Viscount, or a Baron? We don't know (Godalming isn't a real peerage), but we don't really care. He's an English peer. That's all we need.
Since we don't know Lord Godalming's rank he may be higher on the aristocratic ladder than Dracula or lower, but the way people treat him makes me kind of think he's a Viscount or less. He doesn't get the deference that Dracula does.
BUT
That's also a political point by Stoker.
There's a good way of being an aristocrat and a bad way. The bad way is like Count Dracula, who insists on his title, thinks of himself as inherently superior, and (literally) bleeds the people dry.
The good way is Lord "call me Arthur" Godalming, whose rank we never even know.