121111111 has 32 divisors (see below), whose sum is σ = 149299200. Its totient is φ = 96814080.

The previous prime is 121111103. The next prime is 121111121. The reversal of 121111111 is 111111121.

It is not a de Polignac number, because 121111111 - 2³ = 121111103 is a prime.

It is a Duffinian number.

121111111 is a modest number, since divided by 11111 gives 1211 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121111121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 316026 + ... + 316408.

It is an arithmetic number, because the mean of its divisors is an integer number (4665600).

Almost surely, 2^121111111 is an apocalyptic number.

121111111 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

121111111 is a deficient number, since it is larger than the sum of its proper divisors (28188089).

121111111 is a wasteful number, since it uses less digits than its factorization.

121111111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 519.

The product of its digits is 2, while the sum is 10.

The square root of 121111111 is about 11005.0493410979. The cubic root of 121111111 is about 494.7600932480.

Adding to 121111111 its sum of digits (10), we get a palindrome (121111121).

Adding to 121111111 its reverse (111111121), we get a palindrome (232222232).

It can be divided in two parts, 121 and 111111, that multiplied together give a palindrome (13444431).

The spelling of 121111111 in words is "one hundred twenty-one million, one hundred eleven thousand, one hundred eleven".