398715091 has 2 divisors, whose sum is σ = 398715092. Its totient is φ = 398715090.

The previous prime is 398715061. The next prime is 398715139. The reversal of 398715091 is 190517893.

It is a weak prime.

It is an emirp because it is prime and its reverse (190517893) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 398715091 - 2⁹ = 398714579 is a prime.

It is a super-2 number, since 2×398715091² = 317947447582276562, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (398715001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199357545 + 199357546.

It is an arithmetic number, because the mean of its divisors is an integer number (199357546).

Almost surely, 2^398715091 is an apocalyptic number.

398715091 is a deficient number, since it is larger than the sum of its proper divisors (1).

398715091 is an equidigital number, since it uses as much as digits as its factorization.

398715091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 68040, while the sum is 43.

The square root of 398715091 is about 19967.8514367470. The cubic root of 398715091 is about 736.0165125814.

The spelling of 398715091 in words is "three hundred ninety-eight million, seven hundred fifteen thousand, ninety-one".