Adding to 21701 its sum of digits (11), we get a palindrome (21712).
It is a strong prime.
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-21701 is a prime.
It is a Sophie Germain prime.
It is a Chen prime.
It is a Curzon number.
It is a plaindrome in base 15.
It is a congruent number.
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 21701.
221701 is an apocalyptic number.
It is an amenable number.
21701 is an equidigital number, since it uses as much as digits as its factorization.
21701 is an odious number, because the sum of its binary digits is odd.
The square root of 21701 is about 147.3125928086. The cubic root of 21701 is about 27.8928729713.
The spelling of 21701 in words is "twenty-one thousand, seven hundred one", and thus it is an iban number.