Because 69 has an odd number of 1s in its binary representation, it is sometimes called an " odious number ." Of note is that 69 2 ( 4761) and 69 3 ( 328 509) together use every decimal digit from 0-9. 69 is equal to 105 octal, while 105 is equal to 69 hexadecimal. This same property can be applied to all numbers from 64 to 69.