196

Number
$196$ (one hundred and ninety-six) is:


 * $2^2 \times 7^2$


 * The $14$th square number after $1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169$:
 * $196 = 14 \times 14$


 * The $22$nd powerful number after $1, 4, 8, 9, 16, 25, \ldots, 108, 121, 125, 128, 144, 169$


 * The $7$th pentagonal pyramidal number after $1, 6, 12, 40, 75, 126$:
 * $196 = 1 + 5 + 12 + 22 + 35 + 51 + 70 = \dfrac {7^2 \left({7 + 1}\right)} 2$
 * and the $2$nd after $1$ which is square


 * The $6$th heptagonal pyramidal number after $1, 8, 26, 60, 115$:
 * $196 = 1 + 7 + 18 + 34 + 55 + 81 = \dfrac {6 \left({6 + 1}\right) \left({5 \times 6 + 2}\right)} 6$
 * and the $2$nd after $1$ which is square


 * The $12$th positive integer which cannot be expressed as the sum of a square and a prime:
 * $1, 10, 25, 34, 58, 64, 85, 91, 121, 130, 169, 196, \ldots$


 * The $1$st candidate Lychrel number.

Also see

 * Heptagonal Pyramidal Numbers which are Square