21111110321 has 4 divisors (see below), whose sum is σ = 24126983232. Its totient is φ = 18095237412.

The previous prime is 21111110261. The next prime is 21111110351. The reversal of 21111110321 is 12301111112.

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.

It is not a de Polignac number, because 21111110321 - 2²⁶ = 21044001457 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21111110296 and 21111110305.

It is not an unprimeable number, because it can be changed into a prime (21111110351) 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, 1507936445 + ... + 1507936458.

It is an arithmetic number, because the mean of its divisors is an integer number (6031745808).

Almost surely, 2^21111110321 is an apocalyptic number.

It is an amenable number.

21111110321 is a deficient number, since it is larger than the sum of its proper divisors (3015872911).

21111110321 is an equidigital number, since it uses as much as digits as its factorization.

21111110321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3015872910.

The product of its (nonzero) digits is 12, while the sum is 14.

Adding to 21111110321 its reverse (12301111112), we get a palindrome (33412221433).

The spelling of 21111110321 in words is "twenty-one billion, one hundred eleven million, one hundred ten thousand, three hundred twenty-one".