The number 25420
25420 is a composite number with 24 divisors. Its prime factorisation is × 5 × 31 × 41. Divisors (24): 1, 2, 4, 5, 10, 20, 31, 41, 62, 82, 124, 155, 164, 205, 310, 410 … 25420.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 25420: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
25420 is composite. Its prime factorisation is
- 3
The divisors add up to 56448; without 25420 itself that is 31028, so 25420 is abundant (31028 is more than 25420). Euler's totient φ(25420) = 9600 numbers up to 25420 share no factor with it.
- 4
The digits of 25420 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 56 steps to reach 1.
LaTeX source of the formulas on this page
\[ 25420 = 2^{2} \times 5 \times 31 \times 41 \]25420 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 56448 |
| Euler totient φ(n) | 9600 |
| Square | 646176400 |
| Cube | 16425804088000 |
| Square root | 159.436508 (= 2√6355) |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 56 |
| Scientific notation | 2.542 × |
25420 in other forms
| Form | Value |
|---|---|
| In words | twenty-five thousand four hundred and twenty |
| Binary (base 2) | 110001101001100 |
| Octal (base 8) | 61514 |
| Hexadecimal (base 16) | 634C |
| Base 3 | 1021212111 |
| As time | 25420 seconds = 7 h 3 min 40 s |
Is 25420 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (25420 ÷ 2 = 12710) | 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 (25420 ÷ 4 = 6355) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (25420 ÷ 5 = 5084) | 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 3) | 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 (25420 ÷ 10 = 2542) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 10) | 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 25420 a prime number?
No. 25420 = × 5 × 31 × 41, so it is divisible by 2.
What are the factors of 25420?
1, 2, 4, 5, 10, 20, 31, 41, 62, 82, 124, 155, 164, 205, 310, 410, 620, 820, 1271, 2542, 5084, 6355, 12710, 25420.
What is 25420 in binary?
110001101001100 (hexadecimal 634C, octal 61514).
What is the square root of 25420?
About 159.4365, exactly 2√6355.
Is 25420 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 25420?
25420 is a happy number: repeatedly adding the squares of its digits reaches 1.