20321211221 has 4 divisors (see below), whose sum is σ = 20321499552. Its totient is φ = 20320922892.

The previous prime is 20321211193. The next prime is 20321211247. The reversal of 20321211221 is 12211212302.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20321211221 - 2¹⁴ = 20321194837 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20321211221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20321201221) 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 in 3 ways as a sum of consecutive naturals, for example, 39830 + ... + 205496.

It is an arithmetic number, because the mean of its divisors is an integer number (5080374888).

Almost surely, 2^20321211221 is an apocalyptic number.

It is an amenable number.

20321211221 is a deficient number, since it is larger than the sum of its proper divisors (288331).

20321211221 is a wasteful number, since it uses less digits than its factorization.

20321211221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288330.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 20321211221 its reverse (12211212302), we get a palindrome (32532423523).

The spelling of 20321211221 in words is "twenty billion, three hundred twenty-one million, two hundred eleven thousand, two hundred twenty-one".