46

Number
$46$ (forty-six) is:


 * $2 \times 23$


 * The $3$rd of the $1$st ordered quadruple of consecutive integers that have sigma values which are strictly decreasing:
 * $\map \sigma {44} = 84$, $\map \sigma {45} = 78$, $\map \sigma {46} = 72$, $\map \sigma {47} = 48$


 * The smallest positive integer which can be expressed as the sum of $2$ distinct lucky numbers in $5$ different ways:
 * $46 = 3 + 43 = 9 + 37 = 13 + 33 = 15 + 31 = 21 + 25$


 * The $16$th semiprime after $4$, $6$, $9$, $10$, $14$, $15$, $21$, $22$, $25$, $26$, $33$, $34$, $35$, $38$, $39$:
 * $46 = 2 \times 23$


 * The $29$th positive integer after $2$, $3$, $4$, $7$, $8$, $\ldots$, $33$, $37$, $38$, $42$, $43$, $44$, $45$ which cannot be expressed as the sum of distinct pentagonal numbers.