An odious number is a nonnegative number that has an odd number of 1s in its binary expansion. The first few odious numbers are therefore 1, 2, 4, 7, 8, 11, 13, 14, 16, 19, ... (OEIS A000069). Numbers that are not odious are said to be evil numbers.

economical number | evil number | happy number | lucky number | unhappy number | wasteful number