3121111221 has 4 divisors (see below), whose sum is σ = 4161481632. Its totient is φ = 2080740812.

The previous prime is 3121111211. The next prime is 3121111237. The reversal of 3121111221 is 1221111213.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 3121111221 - 2¹⁰ = 3121110197 is a prime.

It is a super-2 number, since 2×3121111221² = 19482670507704221682, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 3121111221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3121111211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 520185201 + ... + 520185206.

It is an arithmetic number, because the mean of its divisors is an integer number (1040370408).

Almost surely, 2^3121111221 is an apocalyptic number.

It is an amenable number.

3121111221 is a deficient number, since it is larger than the sum of its proper divisors (1040370411).

3121111221 is a wasteful number, since it uses less digits than its factorization.

3121111221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1040370410.

The product of its digits is 24, while the sum is 15.

The square root of 3121111221 is about 55866.9063131296. The cubic root of 3121111221 is about 1461.4021715754.

Adding to 3121111221 its reverse (1221111213), we get a palindrome (4342222434).

The spelling of 3121111221 in words is "three billion, one hundred twenty-one million, one hundred eleven thousand, two hundred twenty-one".