21703211 has 2 divisors, whose sum is σ = 21703212. Its totient is φ = 21703210.

The previous prime is 21703181. The next prime is 21703229. The reversal of 21703211 is 11230712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21703211 - 2⁶ = 21703147 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21703211.

It is not a weakly prime, because it can be changed into another prime (21703711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10851605 + 10851606.

It is an arithmetic number, because the mean of its divisors is an integer number (10851606).

Almost surely, 2^21703211 is an apocalyptic number.

21703211 is a deficient number, since it is larger than the sum of its proper divisors (1).

21703211 is an equidigital number, since it uses as much as digits as its factorization.

21703211 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 84, while the sum is 17.

The square root of 21703211 is about 4658.6705185063. The cubic root of 21703211 is about 278.9382022489.

Adding to 21703211 its reverse (11230712), we get a palindrome (32933923).

The spelling of 21703211 in words is "twenty-one million, seven hundred three thousand, two hundred eleven".