828,828

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Number

$828 \, 828$ (eight hundred and twenty-eight thousand, eight hundred and twenty-eight) is:

$2^2 \times 3^2 \times 7 \times 11 \times 13 \times 23$

The $16$th palindromic triangular number after $0$, $1$, $3$, $6$, $55$, $66$, $171$, $595$, $666$, $3003$, $5995$, $8778$, $15 \, 051$, $66 \, 066$, $617 \, 716$:

$828 \, 828 = \dfrac {1287 \times \paren {1287 + 1} } 2$

The $3$rd of those after $55$, $66$, and largest known, which can be split into two palindromic halves

The $1287$th triangular number:

$828 \, 828 = \dfrac {1287 \times \paren {1287 + 1} } 2$

Also see

• Previous: Palindromic Triangular Numbers with Palindromic Halves
• Previous  ... Next: Palindromic Triangular Numbers
• Previous  ... Next: Triangular Number

Sources

• 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $828,828$
• 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $828,828$