The number 31408
31408 is a composite number with 20 divisors. Its prime factorisation is × 13 × 151. Divisors (20): 1, 2, 4, 8, 13, 16, 26, 52, 104, 151, 208, 302, 604, 1208, 1963, 2416 … 31408.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31408: a Harshad number: divisible by its digit sum 16.
- 2
31408 is composite. Its prime factorisation is
- 3
The divisors add up to 65968; without 31408 itself that is 34560, so 31408 is abundant (34560 is more than 31408). Euler's totient φ(31408) = 14400 numbers up to 31408 share no factor with it.
- 4
The digits of 31408 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 85 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31408 = 2^{4} \times 13 \times 151 \]31408 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 20 |
| Sum of divisors | 65968 |
| Euler totient φ(n) | 14400 |
| Square | 986462464 |
| Cube | 30982813069312 |
| Square root | 177.223023 (= 4√1963) |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 85 |
| Scientific notation | 3.1408 × |
31408 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand four hundred and eight |
| Binary (base 2) | 111101010110000 |
| Octal (base 8) | 75260 |
| Hexadecimal (base 16) | 7AB0 |
| Base 3 | 1121002021 |
| As time | 31408 seconds = 8 h 43 min 28 s |
Is 31408 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (31408 ÷ 2 = 15704) | 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 (31408 ÷ 4 = 7852) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 3) | 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 (31408 ÷ 8 = 3926) | 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 8) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 3) | 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 31408 a prime number?
No. 31408 = × 13 × 151, so it is divisible by 2.
What are the factors of 31408?
1, 2, 4, 8, 13, 16, 26, 52, 104, 151, 208, 302, 604, 1208, 1963, 2416, 3926, 7852, 15704, 31408.
What is 31408 in binary?
111101010110000 (hexadecimal 7AB0, octal 75260).
What is the square root of 31408?
About 177.2230, exactly 4√1963.
Is 31408 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 31408?
31408 is a Harshad number: divisible by its digit sum 16.