21110010221 has 2 divisors, whose sum is σ = 21110010222. Its totient is φ = 21110010220.

The previous prime is 21110010199. The next prime is 21110010227. The reversal of 21110010221 is 12201001112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20631013225 + 478996996 = 143635^2 + 21886^2 .

It is a cyclic number.

It is not a de Polignac number, because 21110010221 - 2⁶ = 21110010157 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21110010227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555005110 + 10555005111.

It is an arithmetic number, because the mean of its divisors is an integer number (10555005111).

Almost surely, 2^21110010221 is an apocalyptic number.

It is an amenable number.

21110010221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21110010221 is an equidigital number, since it uses as much as digits as its factorization.

21110010221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21110010221 its reverse (12201001112), we get a palindrome (33311011333).

The spelling of 21110010221 in words is "twenty-one billion, one hundred ten million, ten thousand, two hundred twenty-one".