1,111,111,111

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Number

$1 \, 111 \, 111 \, 111$ is:

$11 \times 41 \times 271 \times 9091$

The $10$th repunit after $1$, $11$, $111$, $1111$, $\ldots$, $111 \, 111 \, 111$

The $103$rd Kaprekar number, and the smallest with $10$ digits:

$1 \, 111 \, 111 \, 111^2 = 1 \, 234 \, 567 \, 900 \, 987 \, 654 \, 321 \to 123 \, 456 \, 790 + 0 \, 987 \, 654 \, 321 = 1 \, 111 \, 111 \, 111$

Also see

• Previous  ... Next: Repunit
• Previous  ... Next: Kaprekar Number

Sources

• 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $297$
• 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $1,111,111,111$
• 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $297$
• 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $1,111,111,111$