The number 12400
12400 is a composite number with 30 divisors. Its prime factorisation is × × 31. Divisors (30): 1, 2, 4, 5, 8, 10, 16, 20, 25, 31, 40, 50, 62, 80, 100, 124 … 12400.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
12400 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
12400 is composite. Its prime factorisation is
- 3
The divisors add up to 30752; without 12400 itself that is 18352, so 12400 is abundant (18352 is more than 12400). Euler's totient φ(12400) = 4800 numbers up to 12400 share no factor with it.
- 4
The digits of 12400 add up to 7, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 156 steps to reach 1.
LaTeX source of the formulas on this page
\[ 12400 = 2^{4} \times 5^{2} \times 31 \]12400 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 30 |
| Sum of divisors | 30752 |
| Euler totient φ(n) | 4800 |
| Square | 153760000 |
| Cube | 1906624000000 |
| Square root | 111.355287 (= 20√31) |
| Digit sum / digital root | 7 / 7 |
| Collatz steps to 1 | 156 |
| Scientific notation | 1.24 × |
12400 in other forms
| Form | Value |
|---|---|
| In words | twelve thousand four hundred |
| Binary (base 2) | 11000001110000 |
| Octal (base 8) | 30160 |
| Hexadecimal (base 16) | 3070 |
| Base 3 | 122000021 |
| As time | 12400 seconds = 3 h 26 min 40 s |
Is 12400 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (12400 ÷ 2 = 6200) | 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 (12400 ÷ 4 = 3100) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (12400 ÷ 5 = 2480) | 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 | Yes (12400 ÷ 8 = 1550) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (12400 ÷ 10 = 1240) | 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 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 12400 a prime number?
No. 12400 = × × 31, so it is divisible by 2.
What are the factors of 12400?
1, 2, 4, 5, 8, 10, 16, 20, 25, 31, 40, 50, 62, 80, 100, 124, 155, 200, 248, 310, 400, 496, 620, 775, 1240, 1550, 2480, 3100, 6200, 12400.
What is 12400 in binary?
11000001110000 (hexadecimal 3070, octal 30160).
What is the square root of 12400?
About 111.3553, exactly 20√31.
Is 12400 divisible by 3?
No. Its digits add up to 7, which is not a multiple of 3.
What is special about the number 12400?
It is a composite number with 30 divisors.