138

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Number

$138$ (one hundred and thirty-eight) is:

$2 \times 3 \times 23$


The $11$th sphenic number after $30$, $42$, $66$, $70$, $78$, $102$, $105$, $110$, $114$, $130$:
$138 = 2 \times 3 \times 23$


Its aliquot sequence terminates in $1$ after $177$ steps.


Also see



Sources

  • 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $276$
  • 1994: Richard K. Guy: Unsolved Problems in Number Theory (2nd ed.)
  • 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $276$
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