21212203321 has 4 divisors (see below), whose sum is σ = 21379228672. Its totient is φ = 21045177972.

The previous prime is 21212203297. The next prime is 21212203349. The reversal of 21212203321 is 12330221212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21212203321 - 2³¹ = 19064719673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21212203351) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 83512485 + ... + 83512738.

It is an arithmetic number, because the mean of its divisors is an integer number (5344807168).

Almost surely, 2^21212203321 is an apocalyptic number.

It is an amenable number.

21212203321 is a deficient number, since it is larger than the sum of its proper divisors (167025351).

21212203321 is a wasteful number, since it uses less digits than its factorization.

21212203321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167025350.

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 21212203321 its reverse (12330221212), we get a palindrome (33542424533).

The spelling of 21212203321 in words is "twenty-one billion, two hundred twelve million, two hundred three thousand, three hundred twenty-one".