I would call that standard form! If you mean scientific form it is 1.55*10^4
Ok, an internet search suggests that standard form is another way of saying scientific form!
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I am amazed Alan !
I was always taught that the world at large would say
$$1.55*10^4$$ is in Scientific Notation.
BUT the English would say it was in Standard Form
This was an irritation to me at school because the two terms were used interchangably and like you I thought an ordinary number should be in standard form.
Now you are English and you say you do not know the term Standard Form !! I am amazed !!