4681

Number
$4681$ (four thousand, six hundred and eighty-one) is:


 * $31 \times 151$


 * The $40$th centered hexagonal number after $1$, $7$, $19$, $37$, $61$, $91$, $127$, $\ldots$, $2791$, $2977$, $3169$, $3367$, $3571$, $3781$, $3997$, $4219$, $4447$:
 * $4681 = \displaystyle 1 + \sum_{k \mathop = 1}^{40 - 1} 6 k = 40^3 - 39^3$


 * The $16$th Poulet number after $341, 561, 645, 1105, 1387, 1729, 1905, 2047, 2465, 2701, 2821, 3277, 4033, 4369, 4371$:
 * $2^{4681} \equiv 2 \pmod {4681}$: $4681 = 31 \times 151$