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.
XXI (formerly, A Feast for Kings (AFFK)) is an American Christian hardcore, metal, and rock band, and they play a version of post-hardcore, progressive metal and progressive rock styles of hardcore punk, metalcore, and rock, with some more melodic hardcore and melodic metalcore elements. They come from Carrollton, Kentucky, where they were formed in 2010, with lead vocalist Eric Gentry. Eric's death in 2014 was the reasoning behind the band's name change, with 'XXI' (Roman numerals for '21') being Eric's age at the time of his death. Their first extended play, Hell on Earth, was released in 2014, shortly before Eric's death, and under their former name. The debut studio album, Inside Out, was released with Carson Butcher as lead vocalist on Tooth & Nail Records in 2015. This album was their breakthrough album on both the Billboard magazine Christian Albums and Heatseekers Albums charts.
The band is from Carrollton, Kentucky, where they formed in 2010 under the name A Feast for Kings, with their members being lead vocalist, Eric Gentry; background vocalist and guitarist, Seth Weigand; guitarist, Jamie King; bassist, Robbie Barnett; and drummer Carson Butcher. After Gentry's death, the group changed their name to XXI to memorialize his age at his time of death. Their drummer went on to become their lead vocalist, and the bassist took over on the drums.
He needs me
He doesn't know it, but he needs me
And so no matter where he goes
Though he doesn't care
He knows that I'm here
He needs me
I ought to leave him, but he needs me
I know that I'm not very bright
Just to tag along
Oh, but right or wrong
I'm his and I'm here
And I'm gonna be his friend or his lover
'Cause my one ambition is
To wake him and make him discover
That he needs me
I've got to follow where he leads me
Or else he'll never know that I need him