398689 has 4 divisors (see below), whose sum is σ = 400660. Its totient is φ = 396720.

The previous prime is 398683. The next prime is 398693. The reversal of 398689 is 986893.

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 153664 + 245025 = 392^2 + 495^2 .

It is a cyclic number.

It is not a de Polignac number, because 398689 - 2³ = 398681 is a prime.

It is a Duffinian number.

398689 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (398681) 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, 642 + ... + 1099.

It is an arithmetic number, because the mean of its divisors is an integer number (100165).

2³⁹⁸⁶⁸⁹ is an apocalyptic number.

It is an amenable number.

398689 is a deficient number, since it is larger than the sum of its proper divisors (1971).

398689 is a wasteful number, since it uses less digits than its factorization.

398689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1970.

The product of its digits is 93312, while the sum is 43.

The square root of 398689 is about 631.4182449059. The cubic root of 398689 is about 73.6000457821.

The spelling of 398689 in words is "three hundred ninety-eight thousand, six hundred eighty-nine".