21220210321 has 2 divisors, whose sum is σ = 21220210322. Its totient is φ = 21220210320.

The previous prime is 21220210307. The next prime is 21220210327. The reversal of 21220210321 is 12301202212.

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., 20004990721 + 1215219600 = 141439^2 + 34860^2 .

It is a cyclic number.

It is not a de Polignac number, because 21220210321 - 2⁹ = 21220209809 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21220210295 and 21220210304.

It is not a weakly prime, because it can be changed into another prime (21220210327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610105160 + 10610105161.

It is an arithmetic number, because the mean of its divisors is an integer number (10610105161).

Almost surely, 2^21220210321 is an apocalyptic number.

It is an amenable number.

21220210321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220210321 is an equidigital number, since it uses as much as digits as its factorization.

21220210321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21220210321 its reverse (12301202212), we get a palindrome (33521412533).

The spelling of 21220210321 in words is "twenty-one billion, two hundred twenty million, two hundred ten thousand, three hundred twenty-one".