The number 31100
31100 is a composite number with 18 divisors. Its prime factorisation is × × 311. Divisors (18): 1, 2, 4, 5, 10, 20, 25, 50, 100, 311, 622, 1244, 1555, 3110, 6220, 7775 … 31100.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31100: a Harshad number: divisible by its digit sum 5.
- 2
31100 is composite. Its prime factorisation is
- 3
The divisors add up to 67704; without 31100 itself that is 36604, so 31100 is abundant (36604 is more than 31100). Euler's totient φ(31100) = 12400 numbers up to 31100 share no factor with it.
- 4
The digits of 31100 add up to 5, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 54 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31100 = 2^{2} \times 5^{2} \times 311 \]31100 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 18 |
| Sum of divisors | 67704 |
| Euler totient φ(n) | 12400 |
| Square | 967210000 |
| Cube | 30080231000000 |
| Square root | 176.351921 (= 10√311) |
| Digit sum / digital root | 5 / 5 |
| Collatz steps to 1 | 54 |
| Scientific notation | 3.11 × |
31100 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand one hundred |
| Binary (base 2) | 111100101111100 |
| Octal (base 8) | 74574 |
| Hexadecimal (base 16) | 797C |
| Base 3 | 1120122212 |
| As time | 31100 seconds = 8 h 38 min 20 s |
Is 31100 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (31100 ÷ 2 = 15550) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (31100 ÷ 4 = 7775) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (31100 ÷ 5 = 6220) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | 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 | No (remainder 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (31100 ÷ 10 = 3110) | 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 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31100 a prime number?
No. 31100 = × × 311, so it is divisible by 2.
What are the factors of 31100?
1, 2, 4, 5, 10, 20, 25, 50, 100, 311, 622, 1244, 1555, 3110, 6220, 7775, 15550, 31100.
What is 31100 in binary?
111100101111100 (hexadecimal 797C, octal 74574).
What is the square root of 31100?
About 176.3519, exactly 10√311.
Is 31100 divisible by 3?
No. Its digits add up to 5, which is not a multiple of 3.
What is special about the number 31100?
31100 is a Harshad number: divisible by its digit sum 5.