21111022111211 has 4 divisors (see below), whose sum is σ = 21111298174032. Its totient is φ = 21110746048392.

The previous prime is 21111022111189. The next prime is 21111022111217. The reversal of 21111022111211 is 11211122011112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21111022111211 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 21111022111211.

It is not an unprimeable number, because it can be changed into a prime (21111022111217) 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, 137916671 + ... + 138069656.

It is an arithmetic number, because the mean of its divisors is an integer number (5277824543508).

Almost surely, 2^{21111022111211} is an apocalyptic number.

21111022111211 is a deficient number, since it is larger than the sum of its proper divisors (276062821).

21111022111211 is an equidigital number, since it uses as much as digits as its factorization.

21111022111211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 276062820.

The product of its (nonzero) digits is 16, while the sum is 17.

Adding to 21111022111211 its reverse (11211122011112), we get a palindrome (32322144122323).

The spelling of 21111022111211 in words is "twenty-one trillion, one hundred eleven billion, twenty-two million, one hundred eleven thousand, two hundred eleven".