21 (twenty-one) is the natural number following 20 and preceding 22.
21 is:
21 has an aliquot sum of 11 though it is the second composite number found in the 11-aliquot tree with the abundant square prime 18 being the first such member. Twenty-one is the first number to be the aliquot sum of three numbers 18, 51, 91.
Love is like oxygen
You get too much you get too high
Not enough and you're gonna die
Love gets you high
Love is like oxygen
. . .
Time on my side
I got it all
I've heard that pride
Always comes before a fall
There's a rumour goin' round the town
That you don't want me around
I can't shake off my city blues
Every way I turn I lose
Love is like oxygen
. . .
Love is like oxygen
. . .
Time is no healer
If you're not there
Lonely fever
Sad words in the air
Some things are better left unsaid
I'm gonna spend my days in bed
I'll walk the streets at night
To be hidden by the city lights
City lights
Love is like oxygen
. . .
Love is like oxygen