21701 has 2 divisors, whose sum is σ = 21702. Its totient is φ = 21700.

The previous prime is 21683. The next prime is 21713. The reversal of 21701 is 10712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21025 + 676 = 145^2 + 26^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-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.

It is not a weakly prime, because it can be changed into another prime (21751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10850 + 10851.

It is an arithmetic number, because the mean of its divisors is an integer number (10851).

2²¹⁷⁰¹ is an apocalyptic number.

It is an amenable number.

21701 is a deficient number, since it is larger than the sum of its proper divisors (1).

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 product of its (nonzero) digits is 14, while the sum is 11.

The square root of 21701 is about 147.3125928086. The cubic root of 21701 is about 27.8928729713.

Adding to 21701 its sum of digits (11), we get a palindrome (21712).

The spelling of 21701 in words is "twenty-one thousand, seven hundred one", and thus it is an iban number.