The number 31420
31420 is a composite number with 12 divisors. Its prime factorisation is × 5 × 1571. Divisors (12): 1, 2, 4, 5, 10, 20, 1571, 3142, 6284, 7855, 15710, 31420.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31420: a Harshad number: divisible by its digit sum 10.
- 2
31420 is composite. Its prime factorisation is
- 3
The divisors add up to 66024; without 31420 itself that is 34604, so 31420 is abundant (34604 is more than 31420). Euler's totient φ(31420) = 12560 numbers up to 31420 share no factor with it.
- 4
The digits of 31420 add up to 10, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 85 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31420 = 2^{2} \times 5 \times 1571 \]31420 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 66024 |
| Euler totient φ(n) | 12560 |
| Square | 987216400 |
| Cube | 31018339288000 |
| Square root | 177.256876 (= 2√7855) |
| Digit sum / digital root | 10 / 1 |
| Collatz steps to 1 | 85 |
| Scientific notation | 3.142 × |
31420 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand four hundred and twenty |
| Binary (base 2) | 111101010111100 |
| Octal (base 8) | 75274 |
| Hexadecimal (base 16) | 7ABC |
| Base 3 | 1121002201 |
| As time | 31420 seconds = 8 h 43 min 40 s |
Is 31420 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (31420 ÷ 2 = 15710) | 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 (31420 ÷ 4 = 7855) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (31420 ÷ 5 = 6284) | 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 4) | 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 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (31420 ÷ 10 = 3142) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 4) | 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 31420 a prime number?
No. 31420 = × 5 × 1571, so it is divisible by 2.
What are the factors of 31420?
1, 2, 4, 5, 10, 20, 1571, 3142, 6284, 7855, 15710, 31420.
What is 31420 in binary?
111101010111100 (hexadecimal 7ABC, octal 75274).
What is the square root of 31420?
About 177.2569, exactly 2√7855.
Is 31420 divisible by 3?
No. Its digits add up to 10, which is not a multiple of 3.
What is special about the number 31420?
31420 is a Harshad number: divisible by its digit sum 10.