398991899 has 2 divisors, whose sum is σ = 398991900. Its totient is φ = 398991898.

The previous prime is 398991863. The next prime is 398991919. The reversal of 398991899 is 998199893.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 398991899 - 2⁸ = 398991643 is a prime.

It is not a weakly prime, because it can be changed into another prime (398991199) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199495949 + 199495950.

It is an arithmetic number, because the mean of its divisors is an integer number (199495950).

Almost surely, 2^398991899 is an apocalyptic number.

398991899 is a deficient number, since it is larger than the sum of its proper divisors (1).

398991899 is an equidigital number, since it uses as much as digits as its factorization.

398991899 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11337408, while the sum is 65.

The square root of 398991899 is about 19974.7815757770. The cubic root of 398991899 is about 736.1867996978.

The spelling of 398991899 in words is "three hundred ninety-eight million, nine hundred ninety-one thousand, eight hundred ninety-nine".