3111111221 has 4 divisors (see below), whose sum is σ = 3111922944. Its totient is φ = 3110299500.

The previous prime is 3111111191. The next prime is 3111111229. The reversal of 3111111221 is 1221111113.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1221111113 = 67 ⋅18225539.

It is a cyclic number.

It is not a de Polignac number, because 3111111221 - 2¹⁴ = 3111094837 is a prime.

It is a super-2 number, since 2×3111111221² = 19358026058864221682, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 3111111196 and 3111111205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3111111229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 400085 + ... + 407786.

It is an arithmetic number, because the mean of its divisors is an integer number (777980736).

Almost surely, 2^3111111221 is an apocalyptic number.

It is an amenable number.

3111111221 is a deficient number, since it is larger than the sum of its proper divisors (811723).

3111111221 is an equidigital number, since it uses as much as digits as its factorization.

3111111221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 811722.

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

The square root of 3111111221 is about 55777.3360873393. The cubic root of 3111111221 is about 1459.8397304838.

Adding to 3111111221 its reverse (1221111113), we get a palindrome (4332222334).

The spelling of 3111111221 in words is "three billion, one hundred eleven million, one hundred eleven thousand, two hundred twenty-one".