Largest Penholodigital Square

Theorem

The largest penholodigital square is $923 \, 187 \, 456$:

$923 \, 187 \, 456 = 30 \, 384^2$

Proof

This theorem requires a proof. In particular: Needs to be demonstrated that there are none higher. Could be done by checking all the squares from $30 \, 385^2$ up to $31 \, 426$ but that's too boring for now. You can help $\mathsf{Pr} \infty \mathsf{fWiki}$ by crafting such a proof. To discuss this page in more detail, feel free to use the talk page. When this work has been completed, you may remove this instance of {{ProofWanted}} from the code. If you would welcome a second opinion as to whether your work is correct, add a call to {{Proofread}} the page.

Sources

• 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $923,187,456$
• 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $923,187,456$