An alternative that works in all math styles...
REVISED SOLUTION (closed circle-arrow)
This is something of a stretch, and so I leave my original solution below. The OP wanted the circle-arrow part of the result to be a closed (not open) circle. Ideally, one could locate such a glyph and substitute its use for the other. However, no such glyph could be located. I was able to make one by superposition, but only in \displaystyle
, so I had to use additional tricks to scale it for the relevant math style. As such, I do not consider this approach ideal.
\documentclass{scrartcl}
\usepackage{stackengine,scalerel,graphicx,amssymb,amsmath,wasysym}
\newsavebox\closedcircleleft
\newsavebox\closedcircleright
\savestack\closedcircleleft{\stackinset{c}{}{c}{}{$\Circle$}{$\circlearrowleft$}}
\savestack\closedcircleright{\stackinset{c}{}{c}{}{$\Circle$}{$\circlearrowright$}}
\DeclareMathOperator*{\sumcirclearrowleft}{%
\ThisStyle{\mathop{\ensurestackMath{\stackinset{c}{-1.5\LMpt}{c}{}{%
\rotatebox[origin=lb]{-90}{$\SavedStyle\scalerel*{\closedcircleleft}{%
i}$}}{\SavedStyle\sum}}}}}
\DeclareMathOperator*{\sumcirclearrowright}{%
\ThisStyle{\mathop{\ensurestackMath{\stackinset{c}{-1.5\LMpt}{c}{}{%
\rotatebox[origin=lb]{90}{$\SavedStyle\scalerel*{\closedcircleright}{%
i}$}}{\SavedStyle\sum}}}}}
\begin{document}
$\displaystyle\sumcirclearrowleft_i^n
\textstyle\sumcirclearrowleft_i^n
\scriptstyle\sumcirclearrowleft_i^n
\scriptscriptstyle\sumcirclearrowleft_i^n$
\medskip
$\displaystyle\sumcirclearrowright_i^n
\textstyle\sumcirclearrowright_i^n
\scriptstyle\sumcirclearrowright_i^n
\scriptscriptstyle\sumcirclearrowright_i^n$
\end{document}

ORIGINAL SOLUTION (open circle-arrow)
\documentclass{scrartcl}
\usepackage{stackengine,scalerel,graphicx,amssymb,amsmath}
\DeclareMathOperator*{\sumcirclearrowleft}{%
\ThisStyle{\mathop{\ensurestackMath{\stackinset{c}{-1.7\LMpt}{c}{.4pt}{%
\rotatebox[origin=lb]{-90}{$\SavedStyle\circlearrowleft$}}{\SavedStyle\sum}}}}}
\DeclareMathOperator*{\sumcirclearrowright}{%
\ThisStyle{\mathop{\ensurestackMath{\stackinset{c}{-1.7\LMpt}{c}{.1pt}{%
\rotatebox[origin=lb]{90}{$\SavedStyle\circlearrowright$}}{\SavedStyle\sum}}}}}
\begin{document}
$\displaystyle\sumcirclearrowleft_i^n
\textstyle\sumcirclearrowleft_i^n
\scriptstyle\sumcirclearrowleft_i^n
\scriptscriptstyle\sumcirclearrowleft_i^n$
\medskip
$\displaystyle\sumcirclearrowright_i^n
\textstyle\sumcirclearrowright_i^n
\scriptstyle\sumcirclearrowright_i^n
\scriptscriptstyle\sumcirclearrowright_i^n$
\end{document}

If one prefers smaller circle-arrows,
\documentclass{scrartcl}
\usepackage{stackengine,scalerel,graphicx,amssymb,amsmath}
\DeclareMathOperator*{\sumcirclearrowleft}{%
\ThisStyle{\mathop{\ensurestackMath{\stackinset{c}{-1.5\LMpt}{c}%
{\dimexpr.9pt-.3\LMpt}{%
\rotatebox[origin=lb]{-90}{$\SavedStyle_\circlearrowleft$}}{\SavedStyle\sum}}}}}
\DeclareMathOperator*{\sumcirclearrowright}{%
\ThisStyle{\mathop{\ensurestackMath{\stackinset{c}{-1.5\LMpt}{c}{.2pt}{%
\rotatebox[origin=lb]{90}{$\SavedStyle_\circlearrowright$}}{\SavedStyle\sum}}}}}
\begin{document}
$\displaystyle\sumcirclearrowleft_i^n
\textstyle\sumcirclearrowleft_i^n
\scriptstyle\sumcirclearrowleft_i^n
\scriptscriptstyle\sumcirclearrowleft_i^n$
\medskip
$\displaystyle\sumcirclearrowright_i^n
\textstyle\sumcirclearrowright_i^n
\scriptstyle\sumcirclearrowright_i^n
\scriptscriptstyle\sumcirclearrowright_i^n$
\end{document}
