121211021111111 has 12 divisors (see below), whose sum is σ = 123301607166000. Its totient is φ = 119155300883808.

The previous prime is 121211021111101. The next prime is 121211021111143. The reversal of 121211021111111 is 111111120112121.

It is a happy number.

It is not a de Polignac number, because 121211021111111 - 2³⁴ = 121193841241927 is a prime.

It is a super-2 number, since 2×121211021111111² (a number of 29 digits) contains 22 as substring.

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 121211021111111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121211021111101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 546576710 + ... + 546798428.

It is an arithmetic number, because the mean of its divisors is an integer number (10275133930500).

Almost surely, 2^{121211021111111} is an apocalyptic number.

121211021111111 is a deficient number, since it is larger than the sum of its proper divisors (2090586054889).

121211021111111 is an equidigital number, since it uses as much as digits as its factorization.

121211021111111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 378886 (or 378827 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 17.

Adding to 121211021111111 its reverse (111111120112121), we get a palindrome (232322141223232).

The spelling of 121211021111111 in words is "one hundred twenty-one trillion, two hundred eleven billion, twenty-one million, one hundred eleven thousand, one hundred eleven".