3131120221 has 2 divisors, whose sum is σ = 3131120222. Its totient is φ = 3131120220.

The previous prime is 3131120189. The next prime is 3131120233. The reversal of 3131120221 is 1220211313.

3131120221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3065283225 + 65836996 = 55365^2 + 8114^2 .

It is an emirp because it is prime and its reverse (1220211313) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3131120221 - 2⁵ = 3131120189 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 3131120195 and 3131120204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3131120821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1565560110 + 1565560111.

It is an arithmetic number, because the mean of its divisors is an integer number (1565560111).

Almost surely, 2^3131120221 is an apocalyptic number.

It is an amenable number.

3131120221 is a deficient number, since it is larger than the sum of its proper divisors (1).

3131120221 is an equidigital number, since it uses as much as digits as its factorization.

3131120221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 3131120221 is about 55956.4135823589. The cubic root of 3131120221 is about 1462.9626805607.

Adding to 3131120221 its reverse (1220211313), we get a palindrome (4351331534).

The spelling of 3131120221 in words is "three billion, one hundred thirty-one million, one hundred twenty thousand, two hundred twenty-one".