The first few numbers not known to produce palindromes when applying the 196-algorithm (that is, a reverse-then-add sequence) are sometimes known as Lychrel numbers. The first few Lychrel numbers are 196, 295, 394, 493, 592, 689, 691, 788, 790, 879, 887, . . . : 887 = 196 + 691 = 295 + 592 = 394 + 493 = 790 + 097.
493 is 13231 in base 4.
493 is the sum of seven consecutive primes: 59 + 61 + 67 + 71 + 73 + 79 + 83 = 493.
493 is the number of Pokémon species, from the first set through the fourth generation.
Source: Wolfram MathWorld
