21221113221 has 72 divisors (see below), whose sum is σ = 38559964352. Its totient is φ = 11008483200.

The previous prime is 21221113189. The next prime is 21221113241. The reversal of 21221113221 is 12231112212.

It is not a de Polignac number, because 21221113221 - 2⁵ = 21221113189 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21221113194 and 21221113203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221113241) 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 in 71 ways as a sum of consecutive naturals, for example, 7141266 + ... + 7144236.

Almost surely, 2^21221113221 is an apocalyptic number.

21221113221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21221113221 is a deficient number, since it is larger than the sum of its proper divisors (17338851131).

21221113221 is a wasteful number, since it uses less digits than its factorization.

21221113221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3943 (or 3929 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

Adding to 21221113221 its reverse (12231112212), we get a palindrome (33452225433).

The spelling of 21221113221 in words is "twenty-one billion, two hundred twenty-one million, one hundred thirteen thousand, two hundred twenty-one".