The number 31138
31138 is a composite number with 4 divisors. Its prime factorisation is 2 × 15569. Divisors (4): 1, 2, 15569, 31138.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31138: a semiprime: 2 × 15569, the product of two primes.
- 2
31138 is composite. Its prime factorisation is
- 3
The divisors add up to 46710; without 31138 itself that is 15572, so 31138 is deficient (15572 is less than 31138). Euler's totient φ(31138) = 15568 numbers up to 31138 share no factor with it.
- 4
The digits of 31138 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 222 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31138 = 2 \times 15569 \]
31138 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 46710 |
| Euler totient φ(n) | 15568 |
| Square | 969575044 |
| Cube | 30190627720072 |
| Square root | 176.459627 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 222 |
| Scientific notation | 3.1138 × |
31138 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand one hundred and thirty-eight |
| Binary (base 2) | 111100110100010 |
| Octal (base 8) | 74642 |
| Hexadecimal (base 16) | 79A2 |
| Base 3 | 1120201021 |
| As time | 31138 seconds = 8 h 38 min 58 s |
Is 31138 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (31138 ÷ 2 = 15569) | 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 | No (remainder 2) | 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 2) | 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 | No (remainder 2) | 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 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 10) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31138 a prime number?
No. 31138 = 2 × 15569, so it is divisible by 2.
What are the factors of 31138?
1, 2, 15569, 31138.
What is 31138 in binary?
111100110100010 (hexadecimal 79A2, octal 74642).
What is the square root of 31138?
About 176.4596.
Is 31138 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 31138?
31138 is a semiprime: 2 × 15569, the product of two primes.