The number 1388
1388 is a composite number with 6 divisors. Its prime factorisation is × 347. Divisors (6): 1, 2, 4, 347, 694, 1388.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
1388 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
1388 is composite. Its prime factorisation is
- 3
The divisors add up to 2436; without 1388 itself that is 1048, so 1388 is deficient (1048 is less than 1388). Euler's totient φ(1388) = 692 numbers up to 1388 share no factor with it.
- 4
The digits of 1388 add up to 20, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 127 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1388 = 2^{2} \times 347 \]1388 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 2436 |
| Euler totient φ(n) | 692 |
| Square | 1926544 |
| Cube | 2674043072 |
| Square root | 37.255872 (= 2√347) |
| Digit sum / digital root | 20 / 2 |
| Collatz steps to 1 | 127 |
| Scientific notation | 1.388 × |
1388 in other forms
| Form | Value |
|---|---|
| In words | one thousand three hundred and eighty-eight |
| Roman numerals | MCCCLXXXVIII |
| Binary (base 2) | 10101101100 |
| Octal (base 8) | 2554 |
| Hexadecimal (base 16) | 56C |
| Base 3 | 1220102 |
| As time | 1388 seconds = 23 min 8 s |
Is 1388 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (1388 ÷ 2 = 694) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (1388 ÷ 4 = 347) | 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 2) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | 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 2) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 8) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1388 a prime number?
No. 1388 = × 347, so it is divisible by 2.
What are the factors of 1388?
1, 2, 4, 347, 694, 1388.
What is 1388 in binary?
10101101100 (hexadecimal 56C, octal 2554).
What is the square root of 1388?
About 37.2559, exactly 2√347.
What is 1388 in Roman numerals?
MCCCLXXXVIII.
Is 1388 divisible by 3?
No. Its digits add up to 20, which is not a multiple of 3.
What is special about the number 1388?
It is a composite number with 6 divisors.