145

Number
$145$ (one hundred and forty-five) is:


 * $5 \times 29$


 * The $10$th pentagonal number after $1, 5, 12, 22, 35, 51, 70, 92, 117$:
 * $145 = 1 + 4 + 7 + 10 + 13 + 16 + 19 + 22 + 25 + 28 = \dfrac {10 \left({3 \times 10 - 1}\right)} 2$


 * The $19$th generalized pentagonal number after $1, 2, 5, 7, 12, 15, 22, 26, 35, 40, 51, 57, 70, 77, 92, 100, 117, 126$:
 * $145 = \dfrac {10 \left({3 \times 10 - 1}\right)} 2$


 * The $3$rd factorion base $10$ after $1, 2$:
 * $145 = 1! + 4! + 5!$


 * The $1$st term of the $3$rd $5$-tuple of consecutive integers have the property that they are not values of the $\sigma$ function $\sigma \left({n}\right)$ for any $n$:
 * $\left({145, 146, 147, 148, 149}\right)$


 * The $6$th positive integer after $50, 65, 85, 125, 130$ which can be expressed as the sum of two square numbers in two or more different ways:
 * $145 = 12^2 + 1^2 = 9^2 + 8^2$