398680309 has 2 divisors, whose sum is σ = 398680310. Its totient is φ = 398680308.

The previous prime is 398680297. The next prime is 398680339. The reversal of 398680309 is 903086893.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 301716900 + 96963409 = 17370^2 + 9847^2 .

It is an emirp because it is prime and its reverse (903086893) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 398680309 - 2¹⁹ = 398156021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (398680339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199340154 + 199340155.

It is an arithmetic number, because the mean of its divisors is an integer number (199340155).

Almost surely, 2^398680309 is an apocalyptic number.

It is an amenable number.

398680309 is a deficient number, since it is larger than the sum of its proper divisors (1).

398680309 is an equidigital number, since it uses as much as digits as its factorization.

398680309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 279936, while the sum is 46.

The square root of 398680309 is about 19966.9804677623. The cubic root of 398680309 is about 735.9951097708.

The spelling of 398680309 in words is "three hundred ninety-eight million, six hundred eighty thousand, three hundred nine".