21101121111111 has 16 divisors (see below), whose sum is σ = 28665869173344. Its totient is φ = 13801897176704.

The previous prime is 21101121111089. The next prime is 21101121111137. The reversal of 21101121111111 is 11111112110112.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21101121111111 - 2¹⁰ = 21101121110087 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101121111011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28978585 + ... + 29697821.

It is an arithmetic number, because the mean of its divisors is an integer number (1791616823334).

Almost surely, 2^{21101121111111} is an apocalyptic number.

21101121111111 is a deficient number, since it is larger than the sum of its proper divisors (7564748062233).

21101121111111 is a wasteful number, since it uses less digits than its factorization.

21101121111111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 903810.

The product of its (nonzero) digits is 4, while the sum is 15.

Adding to 21101121111111 its reverse (11111112110112), we get a palindrome (32212233221223).

Subtracting from 21101121111111 its reverse (11111112110112), we obtain a palindrome (9990009000999).

It can be divided in two parts, 2110112 and 1111111, that multiplied together give a palindrome (2344568654432).

The spelling of 21101121111111 in words is "twenty-one trillion, one hundred one billion, one hundred twenty-one million, one hundred eleven thousand, one hundred eleven".