Odious Number Calculator

The Odious Number Calculator is a free online tool used to check if the number is an odious number.

Odious Number Calculator

Eg, Is 50 an odious number? Enter 50 into the input box and click Calculate button.

What is an odious number?

An odious number is a non-negative integer that has an odd number of 1s in its binary expansion. Therefore, to judge whether a positive integer is an odious number or not, two steps must be taken:

Convert decimal integer to binary.
Count the number of 1s in binary. If the number of 1s is odd, it is an odious number. If the number of 1s is even, it is an evil number.

For example, Is 360 an odious number?

First, Convert 360 to binary.

360 = 101101000

Obviously, there are 4 1s in binary. So, 360 is not an odious number.

First 100 odious numbers

1	2	4	7	8	11	13	14	16	19
21	22	25	26	28	31	32	35	37	38
41	42	44	47	49	50	52	55	56	59
61	62	64	67	69	70	73	74	76	79
81	82	84	87	88	91	93	94	97	98
100	103	104	107	109	110	112	115	117	118
121	122	124	127	128	131	133	134	137	138
140	143	145	146	148	151	152	155	157	158
161	162	164	167	168	171	173	174	176	179
181	182	185	186	188	191	193	194	196	199

How to use the odious number calculator

The procedure to use the odious number calculator is as follows:

1Enter the positive number.
2Click Calculate button to verify whether the input number is an odious number.
3Click the Reset button to start a new verification.

Solved examples using the odious number calculator

Example 1: Is 444 an odious number?

Enter 444 into the input box and click Calculate button, as shown in the figure, 444 is not an odious number.

444 = 110111100

The number of 1s is even. So, 444 is not an odious number, it is an evil number.

Example 2: Is 2023 an odious number?

Enter 2023 into the input box and click Calculate button, as shown in the figure, 2023 is an odious number.

2023 = 11111100111

There are 9 1s in binary. So, 2023 is an odious number.

Odious Number Calculator