121221211111 has 48 divisors (see below), whose sum is σ = 165616766784. Its totient is φ = 86328000000.

The previous prime is 121221211091. The next prime is 121221211121. The reversal of 121221211111 is 111112122121.

It is not a de Polignac number, because 121221211111 - 2¹⁵ = 121221178343 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121221211121) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1057611 + ... + 1166611.

It is an arithmetic number, because the mean of its divisors is an integer number (3450349308).

Almost surely, 2^121221211111 is an apocalyptic number.

121221211111 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

121221211111 is a deficient number, since it is larger than the sum of its proper divisors (44395555673).

121221211111 is a wasteful number, since it uses less digits than its factorization.

121221211111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109144 (or 109133 counting only the distinct ones).

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

Adding to 121221211111 its reverse (111112122121), we get a palindrome (232333333232).

It can be divided in two parts, 12122121 and 1111, that multiplied together give a palindrome (13467676431).

The spelling of 121221211111 in words is "one hundred twenty-one billion, two hundred twenty-one million, two hundred eleven thousand, one hundred eleven".