11211212121111 has 24 divisors (see below), whose sum is σ = 16637247476304. Its totient is φ = 7269689243520.

The previous prime is 11211212121097. The next prime is 11211212121163. The reversal of 11211212121111 is 11112121211211.

11211212121111 is a `hidden beast` number, since 11 + 211 + 212 + 121 + 111 = 666.

It is not a de Polignac number, because 11211212121111 - 2⁶ = 11211212121047 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11211212121211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4676646 + ... + 6655331.

It is an arithmetic number, because the mean of its divisors is an integer number (693218644846).

Almost surely, 2^{11211212121111} is an apocalyptic number.

11211212121111 is a deficient number, since it is larger than the sum of its proper divisors (5426035355193).

11211212121111 is a wasteful number, since it uses less digits than its factorization.

11211212121111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11334991 (or 11334988 counting only the distinct ones).

The product of its digits is 16, while the sum is 18.

Adding to 11211212121111 its reverse (11112121211211), we get a palindrome (22323333332322).

The spelling of 11211212121111 in words is "eleven trillion, two hundred eleven billion, two hundred twelve million, one hundred twenty-one thousand, one hundred eleven".