3131111221 has 24 divisors (see below), whose sum is σ = 3862520640. Its totient is φ = 2522040192.

The previous prime is 3131111183. The next prime is 3131111227. The reversal of 3131111221 is 1221111313.

It is a happy number.

It is not a de Polignac number, because 3131111221 - 2⁹ = 3131110709 is a prime.

It is a super-2 number, since 2×3131111221² = 19607714956544221682, 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 = 3131111195 and 3131111204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3131111227) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 616390 + ... + 621448.

It is an arithmetic number, because the mean of its divisors is an integer number (160938360).

Almost surely, 2^3131111221 is an apocalyptic number.

It is an amenable number.

3131111221 is a deficient number, since it is larger than the sum of its proper divisors (731409419).

3131111221 is a wasteful number, since it uses less digits than its factorization.

3131111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5833 (or 5826 counting only the distinct ones).

The product of its digits is 36, while the sum is 16.

The square root of 3131111221 is about 55956.3331625653. Note that the first 3 decimals coincide. The cubic root of 3131111221 is about 1462.9612788604.

Adding to 3131111221 its reverse (1221111313), we get a palindrome (4352222534).

The spelling of 3131111221 in words is "three billion, one hundred thirty-one million, one hundred eleven thousand, two hundred twenty-one".