21022210021 has 2 divisors, whose sum is σ = 21022210022. Its totient is φ = 21022210020.

The previous prime is 21022210007. The next prime is 21022210031. The reversal of 21022210021 is 12001222012.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11127929121 + 9894280900 = 105489^2 + 99470^2 .

It is a cyclic number.

It is not a de Polignac number, because 21022210021 - 2²⁹ = 20485339109 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21022209983 and 21022210010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21022210031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511105010 + 10511105011.

It is an arithmetic number, because the mean of its divisors is an integer number (10511105011).

Almost surely, 2^21022210021 is an apocalyptic number.

It is an amenable number.

21022210021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21022210021 is an equidigital number, since it uses as much as digits as its factorization.

21022210021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21022210021 its reverse (12001222012), we get a palindrome (33023432033).

The spelling of 21022210021 in words is "twenty-one billion, twenty-two million, two hundred ten thousand, twenty-one".