398809 has 4 divisors (see below), whose sum is σ = 403380. Its totient is φ = 394240.

The previous prime is 398771. The next prime is 398813. The reversal of 398809 is 908893.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 193600 + 205209 = 440^2 + 453^2 .

It is a cyclic number.

It is not a de Polignac number, because 398809 - 2⁷ = 398681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (398819) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2152 + ... + 2329.

It is an arithmetic number, because the mean of its divisors is an integer number (100845).

2³⁹⁸⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

398809 is a deficient number, since it is larger than the sum of its proper divisors (4571).

398809 is an equidigital number, since it uses as much as digits as its factorization.

398809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4570.

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 398809 is about 631.5132619352. The cubic root of 398809 is about 73.6074292477.

The spelling of 398809 in words is "three hundred ninety-eight thousand, eight hundred nine".