Because 69 has an odd number of 1s in its binary representation, it is sometimes called an "odious number." Of note is that 692 (4761) and 693 (328509) together use every decimal digit from 0-9. 69 is equal to 105octal, while 105 is equal to 69 hexadecimal. This same property can be applied to all numbers from 64 to 69.
On many handheld scientific and graphing calculators, the highest factorial that can be calculated, due to memory limitations, is 69! or about 1.711224524×1098.