21110411221 has 2 divisors, whose sum is σ = 21110411222. Its totient is φ = 21110411220.

The previous prime is 21110411213. The next prime is 21110411251. The reversal of 21110411221 is 12211401112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11988060100 + 9122351121 = 109490^2 + 95511^2 .

It is a cyclic number.

It is not a de Polignac number, because 21110411221 - 2³ = 21110411213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21110411195 and 21110411204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21110411251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555205610 + 10555205611.

It is an arithmetic number, because the mean of its divisors is an integer number (10555205611).

Almost surely, 2^21110411221 is an apocalyptic number.

It is an amenable number.

21110411221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21110411221 is an equidigital number, since it uses as much as digits as its factorization.

21110411221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21110411221 its reverse (12211401112), we get a palindrome (33321812333).

The spelling of 21110411221 in words is "twenty-one billion, one hundred ten million, four hundred eleven thousand, two hundred twenty-one".