Change language21 in English words

twenty-one

odd

Square root

4.5825756949558

Binary number

10101

21 in Fibonacci Sequence

Yes

This number consist from

2 digits

Sum of 2 digits (2+1)

3

Composite number (opposite to prime number).

I have a thing with 21. Almost every place I've lived since I moved from my parents' house has had a 21 in the address. Dorm 1121, 1st apt 921, 2nd apt zip ended in ***21, first house 3721, second house 521.