398639 has 4 divisors (see below), whose sum is σ = 419640. Its totient is φ = 377640.

The previous prime is 398627. The next prime is 398669. The reversal of 398639 is 936893.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 936893 = 233 ⋅4021.

It is a cyclic number.

It is not a de Polignac number, because 398639 - 2¹⁶ = 333103 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (398609) 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, 10472 + ... + 10509.

It is an arithmetic number, because the mean of its divisors is an integer number (104910).

2³⁹⁸⁶³⁹ is an apocalyptic number.

398639 is a deficient number, since it is larger than the sum of its proper divisors (21001).

398639 is a wasteful number, since it uses less digits than its factorization.

398639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21000.

The product of its digits is 34992, while the sum is 38.

The square root of 398639 is about 631.3786502567. The cubic root of 398639 is about 73.5969689008.

The spelling of 398639 in words is "three hundred ninety-eight thousand, six hundred thirty-nine".