The number 3123
3123 is a composite number with 6 divisors. Its prime factorisation is × 347. Divisors (6): 1, 3, 9, 347, 1041, 3123.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 3123: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 9.
- 2
3123 is composite. Its prime factorisation is
- 3
The divisors add up to 4524; without 3123 itself that is 1401, so 3123 is deficient (1401 is less than 3123). Euler's totient φ(3123) = 2076 numbers up to 3123 share no factor with it.
- 4
The digits of 3123 add up to 9, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 61 steps to reach 1.
LaTeX source of the formulas on this page
\[ 3123 = 3^{2} \times 347 \]3123 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 4524 |
| Euler totient φ(n) | 2076 |
| Square | 9753129 |
| Cube | 30459021867 |
| Square root | 55.883808 (= 3√347) |
| Digit sum / digital root | 9 / 9 |
| Collatz steps to 1 | 61 |
| Scientific notation | 3.123 × |
3123 in other forms
| Form | Value |
|---|---|
| In words | three thousand one hundred and twenty-three |
| Roman numerals | MMMCXXIII |
| Binary (base 2) | 110000110011 |
| Octal (base 8) | 6063 |
| Hexadecimal (base 16) | C33 |
| Base 3 | 11021200 |
| As time | 3123 seconds = 52 min 3 s |
Is 3123 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (3123 ÷ 3 = 1041) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 3) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 3) | 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (3123 ÷ 9 = 347) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 3) | 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 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 3123 a prime number?
No. 3123 = × 347, so it is divisible by 3.
What are the factors of 3123?
1, 3, 9, 347, 1041, 3123.
What is 3123 in binary?
110000110011 (hexadecimal C33, octal 6063).
What is the square root of 3123?
About 55.8838, exactly 3√347.
What is 3123 in Roman numerals?
MMMCXXIII.
Is 3123 divisible by 3?
Yes. Its digits add up to 9, a multiple of 3.
What is special about the number 3123?
3123 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 9.