The number 31900
31900 is a composite number with 36 divisors. Its prime factorisation is × × 11 × 29. Divisors (36): 1, 2, 4, 5, 10, 11, 20, 22, 25, 29, 44, 50, 55, 58, 100, 110 … 31900.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31900: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
31900 is composite. Its prime factorisation is
- 3
The divisors add up to 78120; without 31900 itself that is 46220, so 31900 is abundant (46220 is more than 31900). Euler's totient φ(31900) = 11200 numbers up to 31900 share no factor with it.
- 4
The digits of 31900 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 147 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31900 = 2^{2} \times 5^{2} \times 11 \times 29 \]31900 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 36 |
| Sum of divisors | 78120 |
| Euler totient φ(n) | 11200 |
| Square | 1017610000 |
| Cube | 32461759000000 |
| Square root | 178.605711 (= 10√319) |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 147 |
| Scientific notation | 3.19 × |
31900 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand nine hundred |
| Binary (base 2) | 111110010011100 |
| Octal (base 8) | 76234 |
| Hexadecimal (base 16) | 7C9C |
| Base 3 | 1121202111 |
| As time | 31900 seconds = 8 h 51 min 40 s |
Is 31900 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (31900 ÷ 2 = 15950) | 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 (31900 ÷ 4 = 7975) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (31900 ÷ 5 = 6380) | 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 1) | 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 4) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (31900 ÷ 10 = 3190) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (31900 ÷ 11 = 2900) | 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 31900 a prime number?
No. 31900 = × × 11 × 29, so it is divisible by 2.
What are the factors of 31900?
1, 2, 4, 5, 10, 11, 20, 22, 25, 29, 44, 50, 55, 58, 100, 110, 116, 145, 220, 275, 290, 319, 550, 580, 638, 725, 1100, 1276, 1450, 1595, 2900, 3190, 6380, 7975, 15950, 31900.
What is 31900 in binary?
111110010011100 (hexadecimal 7C9C, octal 76234).
What is the square root of 31900?
About 178.6057, exactly 10√319.
Is 31900 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 31900?
31900 is a happy number: repeatedly adding the squares of its digits reaches 1.