472
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Number
$472$ (four hundred and seventy-two) is:
- $2^3 \times 59$
- The $5$th positive integer $n$ after $157, 262, 367, 412$ for which $\map \phi {2 n + 1} < \map \phi {2 n}$:
- $\map \phi {2 \times 472 + 1} = 432$, $\map \phi {2 \times 472} = 464$
- The $25$th number whose divisor sum is square:
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- $\map {\sigma_1} {472} = 900 = 30^2$
- The $36$th untouchable number after $2$, $5$, $52$, $88$, $96$, $120$, $124$, $\ldots$, $324$, $326$, $336$, $342$, $372$, $406$, $408$, $426$, $430$, $448$