4095

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Number

$4095$ (four thousand and ninety-five) is:

$3^2 \times 5 \times 7 \times 13$


The $5$th and last Ramanujan-Nagell number after $0$, $1$, $3$, $15$:
$4095 = 2^{12} - 1 = \dfrac {90 \times \paren {90 + 1} } 2$


The $6$th odd abundant number after $945$, $1575$, $2205$, $2835$, $3465$:
$\map {\sigma_1} {4095} - 4095 = 4641 > 4095$


The $90$th triangular number after $1$, $3$, $6$, $10$, $15$, $\ldots$, $3655$, $3741$, $3828$, $3916$, $4005$:
$4095 = \ds \sum_{k \mathop = 1}^{90} k = \dfrac {90 \times \paren {90 + 1} } 2$


Arithmetic Functions on $4095$

\(\ds \map {\sigma_1} { 4095 }\) \(=\) \(\ds 8736\) $\sigma_1$ of $4095$


Also see