The number 1390
1390 is a composite number with 8 divisors. Its prime factorisation is 2 × 5 × 139. Divisors (8): 1, 2, 5, 10, 139, 278, 695, 1390.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1390: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
1390 is composite. Its prime factorisation is
- 3
The divisors add up to 2520; without 1390 itself that is 1130, so 1390 is deficient (1130 is less than 1390). Euler's totient φ(1390) = 552 numbers up to 1390 share no factor with it.
- 4
The digits of 1390 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 127 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1390 = 2 \times 5 \times 139 \]
1390 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 2520 |
| Euler totient φ(n) | 552 |
| Square | 1932100 |
| Cube | 2685619000 |
| Square root | 37.282704 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 127 |
| Scientific notation | 1.39 × |
1390 in other forms
| Form | Value |
|---|---|
| In words | one thousand three hundred and ninety |
| Roman numerals | MCCCXC |
| Binary (base 2) | 10101101110 |
| Octal (base 8) | 2556 |
| Hexadecimal (base 16) | 56E |
| Base 3 | 1220111 |
| As time | 1390 seconds = 23 min 10 s |
Is 1390 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (1390 ÷ 2 = 695) | 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 | No (remainder 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (1390 ÷ 5 = 278) | 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 6) | 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 (1390 ÷ 10 = 139) | 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 10) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1390 a prime number?
No. 1390 = 2 × 5 × 139, so it is divisible by 2.
What are the factors of 1390?
1, 2, 5, 10, 139, 278, 695, 1390.
What is 1390 in binary?
10101101110 (hexadecimal 56E, octal 2556).
What is the square root of 1390?
About 37.2827.
What is 1390 in Roman numerals?
MCCCXC.
Is 1390 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 1390?
1390 is a happy number: repeatedly adding the squares of its digits reaches 1.