133

Number
$133$ (one hundred and thirty-three) is:
 * $7 \times 19$


 * The $7$th octagonal number, after $1$, $8$, $21$, $40$, $65$, $96$:
 * $133 = 1 + 7 + 13 + 19 + 25 + 31 + 37 = 7 \left({3 \times 7 - 2}\right)$


 * The $28$th lucky number:
 * $1, 3, 7, 9, 13, 15, 21, 25, 31, 33, 37, 43, 49, 51, 63, 67, 73, 75, 79, 87, 93, 99, 105, 111, 115, 127, 129, 133, \ldots$


 * The $25$th happy number after $1, 7, 10, 13, 19, 23, \ldots, 91, 94, 97, 100, 103, 109, 129, 130$:
 * $133 \to 1^2 + 3^2 + 3^2 = 1 + 9 + 9 = 19 \to 1^2 + 9^2 = 1 + 81 = 82 \to 8^2 + 2^2 = 64 + 4 = 68 \to 6^2 + 8^2 = 36 + 64 = 100 \to 1^2 + 0^2 + 0^2 = 1$


 * One of the prime factors of one of the terms of one of the $2$ representations of $635 \, 318 \, 657$ as the sum of $2$ fourth powers:
 * $635,318,657 = 133^4 + 134^4$