155

Number
$155$ (one hundred and fifty-five) is:


 * $5 \times 31$


 * The $10$th second pentagonal number after $2$, $7$, $15$, $26$, $40$, $57$, $77$, $100$, $126$:
 * $155 = \dfrac {10 \left({3 \times 10 + 1}\right)} 2$


 * The $20$th generalized pentagonal number after $1$, $2$, $5$, $7$, $12$, $15$, $22$, $26$, $35$, $40$, $51$, $57$, $70$, $77$, $92$, $100$, $117$, $126$, $145$:
 * $155 = \dfrac {10 \left({3 \times 10 + 1}\right)} 2$


 * The $31$st positive integer $n$ such that no factorial of an integer can end with $n$ zeroes.