21112012211111 has 4 divisors (see below), whose sum is σ = 21128365436424. Its totient is φ = 21095658985800.

The previous prime is 21112012211077. The next prime is 21112012211159. The reversal of 21112012211111 is 11111221021112.

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 21112012211111 - 2²⁶ = 21111945102247 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 21112012211111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112012111111) 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, 8176610720 + ... + 8176613301.

It is an arithmetic number, because the mean of its divisors is an integer number (5282091359106).

Almost surely, 2^{21112012211111} is an apocalyptic number.

21112012211111 is a deficient number, since it is larger than the sum of its proper divisors (16353225313).

21112012211111 is a wasteful number, since it uses less digits than its factorization.

21112012211111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16353225312.

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

Adding to 21112012211111 its reverse (11111221021112), we get a palindrome (32223233232223).

The spelling of 21112012211111 in words is "twenty-one trillion, one hundred twelve billion, twelve million, two hundred eleven thousand, one hundred eleven".