21111212112211 has 4 divisors (see below), whose sum is σ = 22735151505472. Its totient is φ = 19487272718952.

The previous prime is 21111212112181. The next prime is 21111212112229. The reversal of 21111212112211 is 11221121211112.

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

It is a cyclic number.

It is not a de Polignac number, because 21111212112211 - 2²⁷ = 21111077894483 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21111212112281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 811969696611 + ... + 811969696636.

It is an arithmetic number, because the mean of its divisors is an integer number (5683787876368).

Almost surely, 2^{21111212112211} is an apocalyptic number.

21111212112211 is a deficient number, since it is larger than the sum of its proper divisors (1623939393261).

21111212112211 is a wasteful number, since it uses less digits than its factorization.

21111212112211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1623939393260.

The product of its digits is 32, while the sum is 19.

Adding to 21111212112211 its reverse (11221121211112), we get a palindrome (32332333323323).

The spelling of 21111212112211 in words is "twenty-one trillion, one hundred eleven billion, two hundred twelve million, one hundred twelve thousand, two hundred eleven".