21110102021 has 2 divisors, whose sum is σ = 21110102022. Its totient is φ = 21110102020.

The previous prime is 21110102009. The next prime is 21110102077. The reversal of 21110102021 is 12020101112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11939932900 + 9170169121 = 109270^2 + 95761^2 .

It is a cyclic number.

It is not a de Polignac number, because 21110102021 - 2³⁴ = 3930232837 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21110101993 and 21110102011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21110102621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555051010 + 10555051011.

It is an arithmetic number, because the mean of its divisors is an integer number (10555051011).

Almost surely, 2^21110102021 is an apocalyptic number.

It is an amenable number.

21110102021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21110102021 is an equidigital number, since it uses as much as digits as its factorization.

21110102021 is an odious number, because the sum of its binary digits is odd.

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

Adding to 21110102021 its reverse (12020101112), we get a palindrome (33130203133).

Subtracting from 21110102021 its reverse (12020101112), we obtain a palindrome (9090000909).

The spelling of 21110102021 in words is "twenty-one billion, one hundred ten million, one hundred two thousand, twenty-one".