The number 31220
31220 is a composite number with 24 divisors. Its prime factorisation is × 5 × 7 × 223. Divisors (24): 1, 2, 4, 5, 7, 10, 14, 20, 28, 35, 70, 140, 223, 446, 892, 1115 … 31220.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
31220 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
31220 is composite. Its prime factorisation is
- 3
The divisors add up to 75264; without 31220 itself that is 44044, so 31220 is abundant (44044 is more than 31220). Euler's totient φ(31220) = 10656 numbers up to 31220 share no factor with it.
- 4
The digits of 31220 add up to 8, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 178 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31220 = 2^{2} \times 5 \times 7 \times 223 \]31220 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 75264 |
| Euler totient φ(n) | 10656 |
| Square | 974688400 |
| Cube | 30429771848000 |
| Square root | 176.691822 (= 2√7805) |
| Digit sum / digital root | 8 / 8 |
| Collatz steps to 1 | 178 |
| Scientific notation | 3.122 × |
31220 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand two hundred and twenty |
| Binary (base 2) | 111100111110100 |
| Octal (base 8) | 74764 |
| Hexadecimal (base 16) | 79F4 |
| Base 3 | 1120211022 |
| As time | 31220 seconds = 8 h 40 min 20 s |
Is 31220 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (31220 ÷ 2 = 15610) | 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 (31220 ÷ 4 = 7805) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (31220 ÷ 5 = 6244) | 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 | Yes (31220 ÷ 7 = 4460) | 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 8) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (31220 ÷ 10 = 3122) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | 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 31220 a prime number?
No. 31220 = × 5 × 7 × 223, so it is divisible by 2.
What are the factors of 31220?
1, 2, 4, 5, 7, 10, 14, 20, 28, 35, 70, 140, 223, 446, 892, 1115, 1561, 2230, 3122, 4460, 6244, 7805, 15610, 31220.
What is 31220 in binary?
111100111110100 (hexadecimal 79F4, octal 74764).
What is the square root of 31220?
About 176.6918, exactly 2√7805.
Is 31220 divisible by 3?
No. Its digits add up to 8, which is not a multiple of 3.
What is special about the number 31220?
It is a composite number with 24 divisors.