74

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

 * Smallest Consecutive Even Nontotients