The number 16641

No. 16641 = 3^2 × 43^2, so it is divisible by 3.

16641 is a perfect square (129²). Its prime factorisation is $3^{2}$ × $43^{2}$ . Divisors (9): 1, 3, 9, 43, 129, 387, 1849, 5547, 16641.

Number

Pick any whole number from 1 to 100,000.

16641 = 3^{2} \times 43^{2}

How to work it out

1
What is special about 16641: a perfect square (129²).
2
16641 is composite. Its prime factorisation is
$16641 = 3^{2} \times 43^{2}$
3
The divisors add up to 24609; without 16641 itself that is 7968, so 16641 is deficient (7968 is less than 16641). Euler's totient φ(16641) = 10836 numbers up to 16641 share no factor with it.
4
The digits of 16641 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 53 steps to reach 1.

LaTeX source of the formulas on this page

\[ 16641 = 3^{2} \times 43^{2} \]

Form	Value
In words	sixteen thousand six hundred and forty-one
Binary (base 2)	100000100000001
Octal (base 8)	40401
Hexadecimal (base 16)	4101
Base 3	211211100
As time	16641 seconds = 4 h 37 min 21 s

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 (16641 ÷ 3 = 5547)	A number is divisible by 3 if the digits add up to a multiple of 3.
4	No (remainder 1)	A number is divisible by 4 if the last two digits make a multiple of 4.
5	No (remainder 1)	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 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 1)	A number is divisible by 8 if the last three digits make a multiple of 8.
9	Yes (16641 ÷ 9 = 1849)	A number is divisible by 9 if the digits add up to a multiple of 9.
10	No (remainder 1)	A number is divisible by 10 if the last digit is 0.
11	No (remainder 9)	A number is divisible by 11 if the alternating sum of the digits is a multiple of 11.
12	No (remainder 9)	A number is divisible by 12 if it is divisible by both 3 and 4.

Is 16641 a prime number?

No. 16641 = $3^{2}$ × $43^{2}$ , so it is divisible by 3.

What are the factors of 16641?

1, 3, 9, 43, 129, 387, 1849, 5547, 16641.

What is 16641 in binary?

100000100000001 (hexadecimal 4101, octal 40401).

What is the square root of 16641?

129, because 129 × 129 = 16641.

Is 16641 divisible by 3?

Yes. Its digits add up to 18, a multiple of 3.

What is special about the number 16641?

16641 is a perfect square (129²).