391013009 has 2 divisors, whose sum is σ = 391013010. Its totient is φ = 391013008.

The previous prime is 391012991. The next prime is 391013089. The reversal of 391013009 is 900310193.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 255360400 + 135652609 = 15980^2 + 11647^2 .

It is a cyclic number.

It is not a de Polignac number, because 391013009 - 2²⁰ = 389964433 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (391013089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195506504 + 195506505.

It is an arithmetic number, because the mean of its divisors is an integer number (195506505).

Almost surely, 2^391013009 is an apocalyptic number.

It is an amenable number.

391013009 is a deficient number, since it is larger than the sum of its proper divisors (1).

391013009 is an equidigital number, since it uses as much as digits as its factorization.

391013009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 729, while the sum is 26.

The square root of 391013009 is about 19774.0488772532. The cubic root of 391013009 is about 731.2463907680.

The spelling of 391013009 in words is "three hundred ninety-one million, thirteen thousand, nine".