21112321221 has 20 divisors (see below), whose sum is σ = 31598524672. Its totient is φ = 14047940808.

The previous prime is 21112321211. The next prime is 21112321259. The reversal of 21112321221 is 12212321112.

21112321221 is a `hidden beast` number, since 211 + 1 + 232 + 1 + 221 = 666.

It is not a de Polignac number, because 21112321221 - 2⁹ = 21112320709 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21112321194 and 21112321203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112321201) 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 19 ways as a sum of consecutive naturals, for example, 206821 + ... + 291546.

Almost surely, 2^21112321221 is an apocalyptic number.

It is an amenable number.

21112321221 is a deficient number, since it is larger than the sum of its proper divisors (10486203451).

21112321221 is an equidigital number, since it uses as much as digits as its factorization.

21112321221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 498902 (or 498893 counting only the distinct ones).

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

Adding to 21112321221 its reverse (12212321112), we get a palindrome (33324642333).

The spelling of 21112321221 in words is "twenty-one billion, one hundred twelve million, three hundred twenty-one thousand, two hundred twenty-one".