21120012221 has 32 divisors (see below), whose sum is σ = 26768351232. Its totient is φ = 16184900160.

The previous prime is 21120012197. The next prime is 21120012253. The reversal of 21120012221 is 12221002112.

It is not a de Polignac number, because 21120012221 - 2¹⁸ = 21119750077 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21120012196 and 21120012205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120062221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3489620 + ... + 3495666.

It is an arithmetic number, because the mean of its divisors is an integer number (836510976).

Almost surely, 2^21120012221 is an apocalyptic number.

It is an amenable number.

21120012221 is a deficient number, since it is larger than the sum of its proper divisors (5648339011).

21120012221 is a wasteful number, since it uses less digits than its factorization.

21120012221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6809.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21120012221 its reverse (12221002112), we get a palindrome (33341014333).

The spelling of 21120012221 in words is "twenty-one billion, one hundred twenty million, twelve thousand, two hundred twenty-one".