Carl Severin Wigert

Carl Severin Wigert (1871–1941) was a Swedish mathematician who created Stieltjes–Wigert polynomials and worked on the divisor function, including correctly describing its maximal order of growth. Wigert proved that
 * $$\limsup_{n\to\infty}\frac{\log d(n)}{\log n/\log\log n}=\log2.$$