3131221213 has 4 divisors (see below), whose sum is σ = 3131343040. Its totient is φ = 3131099388.

The previous prime is 3131221201. The next prime is 3131221241. The reversal of 3131221213 is 3121221313.

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 a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 3121221313 = 7 ⋅445888759.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3131221213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3131221253) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5643 + ... + 79336.

It is an arithmetic number, because the mean of its divisors is an integer number (782835760).

Almost surely, 2^3131221213 is an apocalyptic number.

It is an amenable number.

3131221213 is a deficient number, since it is larger than the sum of its proper divisors (121827).

3131221213 is an equidigital number, since it uses as much as digits as its factorization.

3131221213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121826.

The product of its digits is 216, while the sum is 19.

The square root of 3131221213 is about 55957.3159917450. The cubic root of 3131221213 is about 1462.9784093232.

Adding to 3131221213 its reverse (3121221313), we get a palindrome (6252442526).

It can be divided in two parts, 31312 and 21213, that added together give a palindrome (52525).

The spelling of 3131221213 in words is "three billion, one hundred thirty-one million, two hundred twenty-one thousand, two hundred thirteen".