The number 664
664 is a composite number with 8 divisors. Its prime factorisation is × 83. Divisors (8): 1, 2, 4, 8, 83, 166, 332, 664.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
664 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
664 is composite. Its prime factorisation is
- 3
The divisors add up to 1260; without 664 itself that is 596, so 664 is deficient (596 is less than 664). Euler's totient φ(664) = 328 numbers up to 664 share no factor with it.
- 4
The digits of 664 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 113 steps to reach 1.
LaTeX source of the formulas on this page
\[ 664 = 2^{3} \times 83 \]664 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 1260 |
| Euler totient φ(n) | 328 |
| Square | 440896 |
| Cube | 292754944 |
| Square root | 25.768197 (= 2√166) |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 113 |
| Scientific notation | 6.64 × |
664 in other forms
| Form | Value |
|---|---|
| In words | six hundred and sixty-four |
| Roman numerals | DCLXIV |
| Binary (base 2) | 1010011000 |
| Octal (base 8) | 1230 |
| Hexadecimal (base 16) | 298 |
| Base 3 | 220121 |
| As time | 664 seconds = 11 min 4 s |
Is 664 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (664 ÷ 2 = 332) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 1) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (664 ÷ 4 = 166) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 4) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | A number is divisible by 7 if double the last digit and subtract it from the rest: the result is a multiple of 7. |
| 8 | Yes (664 ÷ 8 = 83) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 4) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 4) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 664 a prime number?
No. 664 = × 83, so it is divisible by 2.
What are the factors of 664?
1, 2, 4, 8, 83, 166, 332, 664.
What is 664 in binary?
1010011000 (hexadecimal 298, octal 1230).
What is the square root of 664?
About 25.7682, exactly 2√166.
What is 664 in Roman numerals?
DCLXIV.
Is 664 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 664?
It is a composite number with 8 divisors.