398193409 has 4 divisors (see below), whose sum is σ = 402136020. Its totient is φ = 394250800.

The previous prime is 398193391. The next prime is 398193449. The reversal of 398193409 is 904391893.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 904391893 = 17737 ⋅50989.

It can be written as a sum of positive squares in 2 ways, for example, as 208167184 + 190026225 = 14428^2 + 13785^2 .

It is a cyclic number.

It is not a de Polignac number, because 398193409 - 2⁷ = 398193281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (398193449) 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 in 3 ways as a sum of consecutive naturals, for example, 1971154 + ... + 1971355.

It is an arithmetic number, because the mean of its divisors is an integer number (100534005).

Almost surely, 2^398193409 is an apocalyptic number.

It is an amenable number.

398193409 is a deficient number, since it is larger than the sum of its proper divisors (3942611).

398193409 is a wasteful number, since it uses less digits than its factorization.

398193409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3942610.

The product of its (nonzero) digits is 209952, while the sum is 46.

The square root of 398193409 is about 19954.7841130893. The cubic root of 398193409 is about 735.6953691899.

The spelling of 398193409 in words is "three hundred ninety-eight million, one hundred ninety-three thousand, four hundred nine".