21111201220111 has 4 divisors (see below), whose sum is σ = 21111741975832. Its totient is φ = 21110660464392.

The previous prime is 21111201220009. The next prime is 21111201220157. The reversal of 21111201220111 is 11102210211112.

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 21111201220111 - 2³³ = 21102611285519 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111201223111) 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, 270319296 + ... + 270397381.

It is an arithmetic number, because the mean of its divisors is an integer number (5277935493958).

Almost surely, 2^{21111201220111} is an apocalyptic number.

21111201220111 is a deficient number, since it is larger than the sum of its proper divisors (540755721).

21111201220111 is an equidigital number, since it uses as much as digits as its factorization.

21111201220111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 540755720.

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

Adding to 21111201220111 its reverse (11102210211112), we get a palindrome (32213411431223).

The spelling of 21111201220111 in words is "twenty-one trillion, one hundred eleven billion, two hundred one million, two hundred twenty thousand, one hundred eleven".