documentclass{article}

usepackage{tikz}
usepackage{pgfplots}
pgfplotsset{compat=1.16}
usepackage{pgfplotstable}

begin{document}

pgfplotstabletypeset[
columns/Iterations/.style={string replace={DIVERGED}{}}]
{
  Iterations
  1421
  DIVERGED
  5362
}

end{document}