394628809 has 2 divisors, whose sum is σ = 394628810. Its totient is φ = 394628808.

The previous prime is 394628807. The next prime is 394628821. The reversal of 394628809 is 908826493.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 381342784 + 13286025 = 19528^2 + 3645^2 .

It is an emirp because it is prime and its reverse (908826493) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 394628809 - 2¹ = 394628807 is a prime.

Together with 394628807, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (394628807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 197314404 + 197314405.

It is an arithmetic number, because the mean of its divisors is an integer number (197314405).

Almost surely, 2^394628809 is an apocalyptic number.

It is an amenable number.

394628809 is a deficient number, since it is larger than the sum of its proper divisors (1).

394628809 is an equidigital number, since it uses as much as digits as its factorization.

394628809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 746496, while the sum is 49.

The square root of 394628809 is about 19865.2663964015. The cubic root of 394628809 is about 733.4934875876.

The spelling of 394628809 in words is "three hundred ninety-four million, six hundred twenty-eight thousand, eight hundred nine".