130

Number
$130$ (one hundred and thirty) is:


 * $2 \times 5 \times 13$


 * The $11$th noncototient after $10, 26, 34, 50, 52, 58, 86, 100, 116, 122$:
 * $\nexists m \in \Z_{>0}: m - \phi \left({m}\right) = 130$
 * where $\phi \left({m}\right)$ denotes the Euler $\phi$ function


 * The $24$th happy number after $1, 7, 10, 13, 19, 23, \ldots, 91, 94, 97, 100, 103, 109, 129$:
 * $130 \to 1^2 + 3^2 + 0^2 = 1 + 9 + 0 = 10 \to 1^2 + 0^2 = 1$


 * The $11$th integer after $7, 13, 19, 35, 38, 41, 57, 65, 70, 125$ the decimal representation of whose square can be split into two parts which are each themselves square:
 * $130^2 = 16 \, 900; 16 = 4^2, 900 = 30^2$


 * The $5$th positive integer after $50, 65, 85, 125$ which can be expressed as the sum of two square numbers in two or more different ways:
 * $130 = 11^2 + 3^2 = 9^2 + 7^2$


 * The $10$th positive integer which cannot be expressed as the sum of a square and a prime:
 * $1, 10, 25, 34, 58, 64, 85, 91, 121, 130, \ldots$


 * The $6$th non-square positive integer which cannot be expressed as the sum of a square and a prime:
 * $10, 34, 58, 85, 91, 130, \ldots$