The number 21004
21004 is a composite number with 12 divisors. Its prime factorisation is × 59 × 89. Divisors (12): 1, 2, 4, 59, 89, 118, 178, 236, 356, 5251, 10502, 21004.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21004 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21004 is composite. Its prime factorisation is
- 3
The divisors add up to 37800; without 21004 itself that is 16796, so 21004 is deficient (16796 is less than 21004). Euler's totient φ(21004) = 10208 numbers up to 21004 share no factor with it.
- 4
The digits of 21004 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 30 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21004 = 2^{2} \times 59 \times 89 \]21004 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 37800 |
| Euler totient φ(n) | 10208 |
| Square | 441168016 |
| Cube | 9266293008064 |
| Square root | 144.927568 (= 2√5251) |
| Digit sum / digital root | 7 / 7 |
| Collatz steps to 1 | 30 |
| Scientific notation | 2.1004 × |
21004 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand and four |
| Binary (base 2) | 101001000001100 |
| Octal (base 8) | 51014 |
| Hexadecimal (base 16) | 520C |
| Base 3 | 1001210221 |
| As time | 21004 seconds = 5 h 50 min 4 s |
Is 21004 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21004 ÷ 2 = 10502) | 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 (21004 ÷ 4 = 5251) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 4) | 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 4) | 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 | No (remainder 4) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 5) | 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 21004 a prime number?
No. 21004 = × 59 × 89, so it is divisible by 2.
What are the factors of 21004?
1, 2, 4, 59, 89, 118, 178, 236, 356, 5251, 10502, 21004.
What is 21004 in binary?
101001000001100 (hexadecimal 520C, octal 51014).
What is the square root of 21004?
About 144.9276, exactly 2√5251.
Is 21004 divisible by 3?
No. Its digits add up to 7, which is not a multiple of 3.
What is special about the number 21004?
It is a composite number with 12 divisors.