385840309 has 2 divisors, whose sum is σ = 385840310. Its totient is φ = 385840308.

The previous prime is 385840253. The next prime is 385840321. The reversal of 385840309 is 903048583.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 359860900 + 25979409 = 18970^2 + 5097^2 .

It is a cyclic number.

It is not a de Polignac number, because 385840309 - 2¹⁹ = 385316021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (385840349) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 192920154 + 192920155.

It is an arithmetic number, because the mean of its divisors is an integer number (192920155).

Almost surely, 2^385840309 is an apocalyptic number.

It is an amenable number.

385840309 is a deficient number, since it is larger than the sum of its proper divisors (1).

385840309 is an equidigital number, since it uses as much as digits as its factorization.

385840309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 103680, while the sum is 40.

The square root of 385840309 is about 19642.8182550264. The cubic root of 385840309 is about 728.0075202751.

The spelling of 385840309 in words is "three hundred eighty-five million, eight hundred forty thousand, three hundred nine".