The number 15664
15664 is a composite number with 20 divisors. Its prime factorisation is × 11 × 89. Divisors (20): 1, 2, 4, 8, 11, 16, 22, 44, 88, 89, 176, 178, 356, 712, 979, 1424 … 15664.
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How to work it out
- 1
What is special about 15664: a Harshad number: divisible by its digit sum 22.
- 2
15664 is composite. Its prime factorisation is
- 3
The divisors add up to 33480; without 15664 itself that is 17816, so 15664 is abundant (17816 is more than 15664). Euler's totient φ(15664) = 7040 numbers up to 15664 share no factor with it.
- 4
The digits of 15664 add up to 22, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 53 steps to reach 1.
LaTeX source of the formulas on this page
\[ 15664 = 2^{4} \times 11 \times 89 \]15664 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 20 |
| Sum of divisors | 33480 |
| Euler totient φ(n) | 7040 |
| Square | 245360896 |
| Cube | 3843333074944 |
| Square root | 125.155903 (= 4√979) |
| Digit sum / digital root | 22 / 4 |
| Collatz steps to 1 | 53 |
| Scientific notation | 1.5664 × |
15664 in other forms
| Form | Value |
|---|---|
| In words | fifteen thousand six hundred and sixty-four |
| Binary (base 2) | 11110100110000 |
| Octal (base 8) | 36460 |
| Hexadecimal (base 16) | 3D30 |
| Base 3 | 210111011 |
| As time | 15664 seconds = 4 h 21 min 4 s |
Is 15664 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (15664 ÷ 2 = 7832) | 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 (15664 ÷ 4 = 3916) | 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 5) | 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 (15664 ÷ 8 = 1958) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | 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 | Yes (15664 ÷ 11 = 1424) | 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 15664 a prime number?
No. 15664 = × 11 × 89, so it is divisible by 2.
What are the factors of 15664?
1, 2, 4, 8, 11, 16, 22, 44, 88, 89, 176, 178, 356, 712, 979, 1424, 1958, 3916, 7832, 15664.
What is 15664 in binary?
11110100110000 (hexadecimal 3D30, octal 36460).
What is the square root of 15664?
About 125.1559, exactly 4√979.
Is 15664 divisible by 3?
No. Its digits add up to 22, which is not a multiple of 3.
What is special about the number 15664?
15664 is a Harshad number: divisible by its digit sum 22.