21003230221 has 2 divisors, whose sum is σ = 21003230222. Its totient is φ = 21003230220.

The previous prime is 21003230219. The next prime is 21003230257. The reversal of 21003230221 is 12203230012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19364114025 + 1639116196 = 139155^2 + 40486^2 .

It is a cyclic number.

It is not a de Polignac number, because 21003230221 - 2¹ = 21003230219 is a prime.

It is a super-2 number, since 2×21003230221² (a number of 21 digits) contains 22 as substring.

Together with 21003230219, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 21003230195 and 21003230204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21003230291) 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, 10501615110 + 10501615111.

It is an arithmetic number, because the mean of its divisors is an integer number (10501615111).

Almost surely, 2^21003230221 is an apocalyptic number.

It is an amenable number.

21003230221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21003230221 is an equidigital number, since it uses as much as digits as its factorization.

21003230221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 16.

Adding to 21003230221 its reverse (12203230012), we get a palindrome (33206460233).

The spelling of 21003230221 in words is "twenty-one billion, three million, two hundred thirty thousand, two hundred twenty-one".