398918917 has 2 divisors, whose sum is σ = 398918918. Its totient is φ = 398918916.

The previous prime is 398918909. The next prime is 398918959. The reversal of 398918917 is 719819893.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 223382916 + 175536001 = 14946^2 + 13249^2 .

It is a cyclic number.

It is not a de Polignac number, because 398918917 - 2³ = 398918909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (398918987) 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, 199459458 + 199459459.

It is an arithmetic number, because the mean of its divisors is an integer number (199459459).

Almost surely, 2^398918917 is an apocalyptic number.

It is an amenable number.

398918917 is a deficient number, since it is larger than the sum of its proper divisors (1).

398918917 is an equidigital number, since it uses as much as digits as its factorization.

398918917 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 979776, while the sum is 55.

The square root of 398918917 is about 19972.9546387108. The cubic root of 398918917 is about 736.1419101805.

The spelling of 398918917 in words is "three hundred ninety-eight million, nine hundred eighteen thousand, nine hundred seventeen".