74

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Number

$74$ (seventy-four) is:

$2 \times 37$


The $1$st element of the $1$st pair of consecutive even nontotients.


The $2$nd of the $2$nd ordered quadruple of consecutive integers that have divisor sums which are strictly increasing:
$\map {\sigma_1} {73} = 74$, $\map {\sigma_1} {74} = 114$, $\map {\sigma_1} {75} = 124$, $\map {\sigma_1} {76} = 140$


The $6$th integer $n$ after $-1$, $0$, $2$, $7$, $15$ such that $\dbinom n 0 + \dbinom n 1 + \dbinom n 2 + \dbinom n 3 = m^2$ for integer $m$:
$\dbinom {74} 0 + \dbinom {74} 1 + \dbinom {74} 2 + \dbinom {74} 3 = 260^2$


The $8$th nontotient after $14$, $26$, $34$, $38$, $50$, $62$, $68$:
$\nexists m \in \Z_{>0}: \map \phi m = 74$
where $\map \phi m$ denotes the Euler $\phi$ function


The $25$th semiprime:
$74 = 2 \times 37$


The $28$th of $35$ integers less than $91$ to which $91$ itself is a Fermat pseudoprime:
$3$, $4$, $9$, $10$, $12$, $16$, $17$, $22$, $23$, $25$, $27$, $29$, $30$, $36$, $38$, $40$, $43$, $48$, $51$, $53$, $55$, $61$, $62$, $64$, $66$, $68$, $69$, $74$, $\ldots$


Also see



Sources