21111113321 has 4 divisors (see below), whose sum is σ = 21111702144. Its totient is φ = 21110524500.

The previous prime is 21111113311. The next prime is 21111113327. The reversal of 21111113321 is 12331111112.

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 a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21111113321 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21111113321.

It is not an unprimeable number, because it can be changed into a prime (21111113327) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 236885 + ... + 313586.

It is an arithmetic number, because the mean of its divisors is an integer number (5277925536).

Almost surely, 2^21111113321 is an apocalyptic number.

It is an amenable number.

21111113321 is a deficient number, since it is larger than the sum of its proper divisors (588823).

21111113321 is an equidigital number, since it uses as much as digits as its factorization.

21111113321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 588822.

The product of its digits is 36, while the sum is 17.

Adding to 21111113321 its reverse (12331111112), we get a palindrome (33442224433).

The spelling of 21111113321 in words is "twenty-one billion, one hundred eleven million, one hundred thirteen thousand, three hundred twenty-one".