161

Number
$161$ (one hundred and sixty-one) is:


 * $7 \times 23$


 * The $6$th hexagonal pyramidal number after $1$, $7$, $22$, $50$, $95$:
 * $161 = \displaystyle \sum_{k \mathop = 1}^6 k \left({2 k - 1}\right) = \dfrac {6 \left({6 + 1}\right) \left({4 \times 6 - 1}\right)} 6$


 * The $6$th Cullen number after $1$, $3$, $9$, $25$, $65$:
 * $161 = 5 \times 2^5 + 1$


 * The $7$th inconsummate number after $62$, $63$, $65$, $75$, $84$, $95$:
 * $\nexists n \in \Z_{>0}: n = 161 \times s_{10} \left({n}\right)$


 * The largest integer that cannot be expressed as the sum of distinct primes of the form $6 n - 1$.


 * The $32$nd positive integer $n$ such that no factorial of an integer can end with $n$ zeroes.