21112112321 has 16 divisors (see below), whose sum is σ = 22319712000. Its totient is φ = 19930392768.

The previous prime is 21112112237. The next prime is 21112112323. The reversal of 21112112321 is 12321121112.

It is a happy number.

It is not a de Polignac number, because 21112112321 - 2³⁴ = 3932243137 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21112112321.

It is not an unprimeable number, because it can be changed into a prime (21112112323) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 518420 + ... + 557658.

It is an arithmetic number, because the mean of its divisors is an integer number (1394982000).

Almost surely, 2^21112112321 is an apocalyptic number.

It is an amenable number.

21112112321 is a deficient number, since it is larger than the sum of its proper divisors (1207599679).

21112112321 is a wasteful number, since it uses less digits than its factorization.

21112112321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39568.

The product of its digits is 48, while the sum is 17.

Adding to 21112112321 its reverse (12321121112), we get a palindrome (33433233433).

The spelling of 21112112321 in words is "twenty-one billion, one hundred twelve million, one hundred twelve thousand, three hundred twenty-one".