The number 1387
1387 is a composite number with 4 divisors. Its prime factorisation is 19 × 73. Divisors (4): 1, 19, 73, 1387.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1387: a Harshad number: divisible by its digit sum 19; a semiprime: 19 × 73, the product of two primes.
- 2
1387 is composite. Its prime factorisation is
- 3
The divisors add up to 1480; without 1387 itself that is 93, so 1387 is deficient (93 is less than 1387). Euler's totient φ(1387) = 1296 numbers up to 1387 share no factor with it.
- 4
The digits of 1387 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 65 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1387 = 19 \times 73 \]
1387 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 1480 |
| Euler totient φ(n) | 1296 |
| Square | 1923769 |
| Cube | 2668267603 |
| Square root | 37.242449 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 65 |
| Scientific notation | 1.387 × |
1387 in other forms
| Form | Value |
|---|---|
| In words | one thousand three hundred and eighty-seven |
| Roman numerals | MCCCLXXXVII |
| Binary (base 2) | 10101101011 |
| Octal (base 8) | 2553 |
| Hexadecimal (base 16) | 56B |
| Base 3 | 1220101 |
| As time | 1387 seconds = 23 min 7 s |
Is 1387 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 | No (remainder 1) | 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 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 1) | 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 | No (remainder 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 7) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 1) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1387 a prime number?
No. 1387 = 19 × 73, so it is divisible by 19.
What are the factors of 1387?
1, 19, 73, 1387.
What is 1387 in binary?
10101101011 (hexadecimal 56B, octal 2553).
What is the square root of 1387?
About 37.2424.
What is 1387 in Roman numerals?
MCCCLXXXVII.
Is 1387 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 1387?
1387 is a Harshad number: divisible by its digit sum 19; a semiprime: 19 × 73, the product of two primes.