3121111121 has 4 divisors (see below), whose sum is σ = 3143893092. Its totient is φ = 3098329152.

The previous prime is 3121111111. The next prime is 3121111139. The reversal of 3121111121 is 1211111213.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1008697600 + 2112413521 = 31760^2 + 45961^2 .

It is a cyclic number.

It is not a de Polignac number, because 3121111121 - 2¹⁸ = 3120848977 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 3121111096 and 3121111105.

It is not an unprimeable number, because it can be changed into a prime (3121111111) 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 3 ways as a sum of consecutive naturals, for example, 11390780 + ... + 11391053.

It is an arithmetic number, because the mean of its divisors is an integer number (785973273).

Almost surely, 2^3121111121 is an apocalyptic number.

It is an amenable number.

3121111121 is a deficient number, since it is larger than the sum of its proper divisors (22781971).

3121111121 is a wasteful number, since it uses less digits than its factorization.

3121111121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22781970.

The product of its digits is 12, while the sum is 14.

The square root of 3121111121 is about 55866.9054181454. The cubic root of 3121111121 is about 1461.4021559677.

Adding to 3121111121 its reverse (1211111213), we get a palindrome (4332222334).

It can be divided in two parts, 3 and 121111121, that multiplied together give a palindrome (363333363).

The spelling of 3121111121 in words is "three billion, one hundred twenty-one million, one hundred eleven thousand, one hundred twenty-one".