771

Number
$730$ (seven hundred and thirty) is:
 * $2 \times 5 \times 73$


 * The $25$th positive integer which cannot be expressed as the sum of a square and a prime:
 * $1, 10, 25, 34, 58, 64, 85, 91, 121, 130, 169, 196, 214, 226, 289, 324, 370, 400, 526, 529, 625, 676, 706, 730, 771, \ldots$


 * The $13$th non-square positive integer which cannot be expressed as the sum of a square and a prime:
 * $10, 34, 58, 85, 91, 130, 214, 226, 370, 526, 706, 730, 771, \ldots$