331312021 has 4 divisors (see below), whose sum is σ = 339392844. Its totient is φ = 323231200.

The previous prime is 331312019. The next prime is 331312027. The reversal of 331312021 is 120213133.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10400625 + 320911396 = 3225^2 + 17914^2 .

It is a cyclic number.

It is not a de Polignac number, because 331312021 - 2¹ = 331312019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 331311986 and 331312004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (331312027) 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, 4040350 + ... + 4040431.

It is an arithmetic number, because the mean of its divisors is an integer number (84848211).

Almost surely, 2^331312021 is an apocalyptic number.

It is an amenable number.

331312021 is a deficient number, since it is larger than the sum of its proper divisors (8080823).

331312021 is an equidigital number, since it uses as much as digits as its factorization.

331312021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8080822.

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

The square root of 331312021 is about 18201.9784913619. The cubic root of 331312021 is about 691.9569322044.

Adding to 331312021 its reverse (120213133), we get a palindrome (451525154).

The spelling of 331312021 in words is "three hundred thirty-one million, three hundred twelve thousand, twenty-one".