# Square whose Sigma is Cubic

## Theorem

The number $1 \, 857 \, 437 \, 604$ is a square number whose $\sigma$ value is a cube.

## Proof

 $\displaystyle 1 \, 857 \, 437 \, 604$ $=$ $\displaystyle 43 \, 098^2$ $\displaystyle \map \sigma {1 \, 857 \, 437 \, 604}$ $=$ $\displaystyle 5 \, 168 \, 743 \, 489$ $\sigma$ of $1 \, 857 \, 437 \, 604$ $\displaystyle$ $=$ $\displaystyle 1729^3$

$\blacksquare$