3131320021 has 2 divisors, whose sum is σ = 3131320022. Its totient is φ = 3131320020.

The previous prime is 3131319991. The next prime is 3131320051. The reversal of 3131320021 is 1200231313.

3131320021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a balanced prime because it is at equal distance from previous prime (3131319991) and next prime (3131320051).

It can be written as a sum of positive squares in only one way, i.e., 1917564100 + 1213755921 = 43790^2 + 34839^2 .

It is a cyclic number.

It is not a de Polignac number, because 3131320021 - 2²⁵ = 3097765589 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 3131319977 and 3131320004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3131320051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1565660010 + 1565660011.

It is an arithmetic number, because the mean of its divisors is an integer number (1565660011).

Almost surely, 2^3131320021 is an apocalyptic number.

It is an amenable number.

3131320021 is a deficient number, since it is larger than the sum of its proper divisors (1).

3131320021 is an equidigital number, since it uses as much as digits as its factorization.

3131320021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108, while the sum is 16.

The square root of 3131320021 is about 55958.1988720152. The cubic root of 3131320021 is about 1462.9937976164.

Adding to 3131320021 its reverse (1200231313), we get a palindrome (4331551334).

The spelling of 3131320021 in words is "three billion, one hundred thirty-one million, three hundred twenty thousand, twenty-one".