2178

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Number

$2178$ (two thousand, one hundred and seventy-eight) is:

$2 \times 3^2 \times 11^2$

The $2$nd of only $2$ numbers with $4$ digits or fewer which has a multiple which is its reversal:

$2178 \times 4 = 8712$

A $4$th order recurring digital invariant:

$2^4 + 1^4 + 7^4 + 8^4 = 6514$; $6^4 + 5^4 + 1^4 + 4^4 = 2178$

Also see

• Previous  ... Next: Ratio of Number to Reversal which is Multiple

Sources

• 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $1089$
• 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $2178$
• 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $1089$
• 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $2178$