Am I unusual in having no sensory memory at all, visual , audio , smell

No, you aren’t alone in this – the same pretty much applies to me, including the lack of involuntary "perceptive imagination" (visuals, smells, sounds etc.), which apparently is rather atypical for aphantasia. Same goes for our math skills.
Others said they initially had issues with multiplication – which I always have been decent at. They usually also said that they do not see any appeal in fictional literature, especially fantasy – while it is actually one of my favorite genres.
So allow me to ask a couple questions:
Do you like Fantasy, Science Fiction and Science Fantasy literature?
Are you religious?
Do you remember ever having had one instant of visual imagination (especially involuntary/dreams/nightmares)?
Do you have any artistical skills or interests? (drawing, sketching, music etc. pp.)

As the first commenter said, no you’re definitely not alone in this, although as alluded to there is what seems to be a spectrum of aphantasia, we assume everyone has the lack of visual minds eye, because that is how it is usually realised, but also includes the other imaginations that people have, smell, sounds, taste. I personally lack all of these too, and I know it came as quite a shock to me to realise that this was something other people were experiencing as part of their normal day to day life!
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I’m quite sure there are probably a decent percentage of the global population out there who have no idea that the way they experience is any different from anyone else, why would you after all? The only thing that made me suspect  was people talking about visualizing things to help remember, and at the time thinking this is surely metaphorical. But it wasn’t till around 2015 when I saw an article on BBC detailing some research it really twigged.
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Personally I think though that it’s important not to focus on it as a weakness, as you say you did well academically and it allows you to move on with things quickly, but I do have a kind of jealous that others are having a potentially richer tapastry to experiences, although whether that’s always positive or not is of course open to debate!

No kidding there’s a spectrum. I have absolutely no sensory recall or reconstruction ability in my mind. I don’t even hear my own voice unless I’m actually talking. However I’ve dreamt my whole life and they were vivid, every one of the senses seemed to be engaged. For the most part, in the immediate i remember what I dreamed but it fades fast. Most importantly the only dreams I ever have/had, all seem like nightmares.

Throughout my years I have been artistic, (art & music) and athletic. However I do tend to be more athletically inclined becuase it feels easier. I absolutely believe in God and Jesus, I just hate religion.

I love to read I’ve always been strong in math and science. I tend to have really good mental math skills as long as it’s not four digits or more. And as far as genre for entertainment reading, i have and will read anything but I prefer fantasy over fiction. Reality is all I can get naturally so I try to change it up when I can.

I like to think our ability to move on from issues, get over things and not get hung up on emotional bias that comes with memory is absolutey our superpower.

Yeah, we’re not alone. I experience no sensory memory, no mind-movie when reading, and no inner-monologue. And each them is blowing my mind in their own unique way. I’m on the heels of 40 and this realization makes me feel like I’m at a disadvantage, like life for others is on easy mode. 

I’d agree, although I very occasionally get a flash of a dull picture if it’s something that was emotional, day to day I get nothing. I can’t recall smells, I struggle like so many with faces and names, very often my memory of who someone is triggers as I’m speaking to them. For years I developed a friendly patter that I used to find out about people at parties without them realising. These days I will just say I’m Aphantasia and the interest will help us establish our history.

I’m a successful software engineer, although my job is now more business analyst.I never really had any inclination I was different although my ability to create analogies and models of things is super good. No idea if that is related. I’m not however artistic 🙂 I can draw you a map of where I lived when I was 10 but I can’t tell you what the building I lived in looked like.

Have any of you asked parents, my mum is exactly the same as me, we spoke about it this Christmas.

(Oh I should add, my fiance thinks it’s hilarious that I can’t recognise an actor in a film if any aspect of them is different from some character that I remember from another film.)