284

Number
$284$ (two hundred and eighty-four) is:


 * $2^2 \times 71$


 * The $45$th nontotient:
 * $\nexists m \in \Z_{>0}: \phi \left({m}\right) = 284$
 * where $\phi \left({m}\right)$ denotes the Euler $\phi$ function


 * The $3$rd integer solution to $\sigma \left({n}\right) = \sigma \left({n + 2}\right)$ after $33, 54$:
 * $\sigma \left({284}\right) = 504 = \sigma \left({286}\right)$


 * The larger of the $1$st amicable pair, with $220$:
 * $\sigma \left({220}\right) = \sigma \left({284}\right) = 504 = 220 + 284$
 * which is also the first Thabit pair:
 * $220 = 2^2 \times 11 \times 5 = 2^2 \left({3 \times 2^2 - 1}\right) \left({3 \times 2^{2 - 1} - 1}\right), 224 = 2^2 \left({9 \times 2^{2 \times 2 - 1} - 1}\right)$