331243009 has 2 divisors, whose sum is σ = 331243010. Its totient is φ = 331243008.

The previous prime is 331243007. The next prime is 331243013. The reversal of 331243009 is 900342133.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 256800625 + 74442384 = 16025^2 + 8628^2 .

It is an emirp because it is prime and its reverse (900342133) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 331243009 - 2¹ = 331243007 is a prime.

It is a super-2 number, since 2×331243009² = 219443862022748162, which contains 22 as substring.

Together with 331243007, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (331243007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165621504 + 165621505.

It is an arithmetic number, because the mean of its divisors is an integer number (165621505).

Almost surely, 2^331243009 is an apocalyptic number.

It is an amenable number.

331243009 is a deficient number, since it is larger than the sum of its proper divisors (1).

331243009 is an equidigital number, since it uses as much as digits as its factorization.

331243009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1944, while the sum is 25.

The square root of 331243009 is about 18200.0826646474. The cubic root of 331243009 is about 691.9088841965.

The spelling of 331243009 in words is "three hundred thirty-one million, two hundred forty-three thousand, nine".