23 (twenty-three) is the natural number following 22 and preceding 24.
Twenty-three is the ninth prime number, the smallest odd prime that is not a twin prime. Twenty-three is also the fifth factorial prime, the second Woodall prime. It is an Eisenstein prime with no imaginary part and real part of the form 3n − 1.
Twenty-three is the sum of three other, consecutive, prime numbers; 5, 7 and 11. It is the first prime number showing this characteristic.
The fifth Sophie Germain prime and the fourth safe prime, 23 is the next to last member of the first Cunningham chain of the first kind to have five terms (2, 5, 11, 23, 47). Since 14! + 1 is a multiple of 23 but 23 is not one more than a multiple 14, 23 is a Pillai prime. 23 is the smallest odd prime to be a highly cototient number, as the solution to x − φ(x) for the integers 95, 119, 143, 529.
Twenty-three is the aliquot sum of two integers; the discrete semiprimes 57 and 85 and is the base of the 23-aliquot tree.
23 is the first prime p for which unique factorization of cyclotomic integers based on the pth root of unity breaks down.
You can count on him.
He'll always let you down.
While you hang about for him.
He's in another town.
He gets from A to B,
He can't see eye to eye,
With anyone... If you ask me...
He doesn't try
Check his empty pockets
Check 'em more than once
He hasn't got it,
Whatever it is that you want.
Energy is a four letter word
He doesn't buy
Here he comes now - 23rd
He doesn't try
Compassion, it isn't necessary
His sickness is an act
He'll make you an accessory
After this obvious fact
You must excuse him
Ask his Mother why
You can't abuse him
He doesn't try
It doesn't pay to help him
he's somewhere else
Tell 'im - you can't tell him
He's a fool to himself
"What's in it for me" - you know the kind
Always saying "Why?"
Two weeks behind
He doesn't try
Bikes, buses, trucks, and trains,
Gangways, ladders, and ramps
A seemingly endless chain
of pickpockets and tramps
He wears the look of false
alarm like an old school tie
Somone ought to twist his arm
he doesn't try
Laugh? It isn't funny
No respect for pain
If you give him money
He slings it down the drain
You're looking for Mr. Right
His type need not apply
He won't play the white man