# (9, 21)

A = 9

B = 21

 Sum 30 Difference 12 A × B 189 A ÷ B 0.428571 B ÷ A 2.33333 GCD 3 LCM 63 Average 15

## Combination

293930

${}_{ 21 } C_{ 9 } = 293930$

## Sum of squares

522

$9^2 + 21^2 = 522$

## Norm

$\sqrt{ 9^2 + 21^2 } = 22.847319317591726$

## Geometric mean

13.74772708486752

No

## Stirling number of the first kind

0

$S(9,\ 21) = 0$

## Stirling number of the second kind

0

$S(9,\ 21) = 0$

## Jacobi symbol

0

$\left(\dfrac{ 9 }{ 21 }\right) = 0$

## Properties of 9 and 21

Properties of 9 and 21: The GCD and LCM of 9 and 21 are 3 and 63 respectively. 9 + 21 = 30, |9 - 21| = 12, 9 * 21 = 189, 9 / 21 = 0.42857142857142855, 21 / 9 = 2.3333333333333335. The average of 9 and 21 is 15 and the norm of them is 22.847319317591726. The geometric mean of two numbers is 13.74772708486752.