1177

From ProofWiki
Jump to navigation Jump to search

Previous  ... Next

Number

$1177$ (one thousand, one hundred and seventy-seven) is:

$11 \times 107$


The $22$nd heptagonal number after $1$, $7$, $18$, $34$, $55$, $81$, $112$, $148$, $189$, $235$, $286$, $342$, $403$, $469$, $540$, $616$, $697$, $783$, $874$, $970$, $1071$:
$\ds 1177 = \sum_{k \mathop = 1}^{22} \paren {5 k - 4} = \dfrac {22 \paren {5 \times 22 - 3} } 2$


Also see