399395819 has 2 divisors, whose sum is σ = 399395820. Its totient is φ = 399395818.

The previous prime is 399395809. The next prime is 399395833. The reversal of 399395819 is 918593993.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 399395819 - 2²⁸ = 130960363 is a prime.

It is a super-2 number, since 2×399395819² = 319034040469361522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (399395809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199697909 + 199697910.

It is an arithmetic number, because the mean of its divisors is an integer number (199697910).

Almost surely, 2^399395819 is an apocalyptic number.

399395819 is a deficient number, since it is larger than the sum of its proper divisors (1).

399395819 is an equidigital number, since it uses as much as digits as its factorization.

399395819 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2361960, while the sum is 56.

The square root of 399395819 is about 19984.8897670215. The cubic root of 399395819 is about 736.4351424877.

The spelling of 399395819 in words is "three hundred ninety-nine million, three hundred ninety-five thousand, eight hundred nineteen".