21111212122111 has 8 divisors (see below), whose sum is σ = 22353210303840. Its totient is φ = 19869231959808.

The previous prime is 21111212122081. The next prime is 21111212122151. The reversal of 21111212122111 is 11122121211112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21111212122111 - 2²¹ = 21111210024959 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 (21111212122151) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2054691 + ... + 6814996.

It is an arithmetic number, because the mean of its divisors is an integer number (2794151287980).

Almost surely, 2^{21111212122111} is an apocalyptic number.

21111212122111 is a deficient number, since it is larger than the sum of its proper divisors (1241998181729).

21111212122111 is a wasteful number, since it uses less digits than its factorization.

21111212122111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9009713.

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

Adding to 21111212122111 its reverse (11122121211112), we get a palindrome (32233333333223).

The spelling of 21111212122111 in words is "twenty-one trillion, one hundred eleven billion, two hundred twelve million, one hundred twenty-two thousand, one hundred eleven".