Firstly, I'd suggest setting the float using
\begin{figure}[p]
% figure content here
\end{figure}
This would allow the float to be placed within the text, yet float to a page on its own. Secondly, use fancyhdr to design a float-specific page style that sets the page number lower than usual. Finally, use floatpag to specify this new float page style for that specific float:

\documentclass{article}
\usepackage{graphicx,floatpag,fancyhdr}
\usepackage{lipsum}
% This defines the fancy page style to be similar to plain
\pagestyle{fancy}
\fancyhf{}% Clear header/footer
\fancyfoot[C]{\thepage}
\renewcommand{\headrulewidth}{0pt}% Remove header rule
% Page style plainlower is similar to plain, but lowers page number by 6 lines of text
\fancypagestyle{plainlower}{
\fancyhf{}% Clear header/footer
\fancyfoot[C]{\raisebox{-6\baselineskip}{\thepage}}
\renewcommand{\headrulewidth}{0pt}% Remove header rule
}
\begin{document}
\lipsum[1-2]
\begin{figure}[p]
\thisfloatpagestyle{plainlower}
\centering
\includegraphics[height=1.1\textheight]{example-image-9x16}
\caption{A very large figure}
\end{figure}
\lipsum[3-10]
\end{document}
Related reference: Suppress page number for a single page that only contains one large table?
\begin{figure}[p]...\end{figure}? – Werner Sep 07 '16 at 19:04[htb]???? – David Carlisle Sep 07 '16 at 19:19LaTeX Warning: Float too large for page by 55.00336pt on input line 9.which would be an indication of how far to move the number – David Carlisle Sep 07 '16 at 19:48