398657 has 4 divisors (see below), whose sum is σ = 455616. Its totient is φ = 341700.

The previous prime is 398627. The next prime is 398669. The reversal of 398657 is 756893.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 756893 = 53 ⋅14281.

It is a cyclic number.

It is not a de Polignac number, because 398657 - 2¹⁰ = 397633 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 398657.

It is not an unprimeable number, because it can be changed into a prime (398627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28469 + ... + 28482.

It is an arithmetic number, because the mean of its divisors is an integer number (113904).

2³⁹⁸⁶⁵⁷ is an apocalyptic number.

It is an amenable number.

398657 is a deficient number, since it is larger than the sum of its proper divisors (56959).

398657 is an equidigital number, since it uses as much as digits as its factorization.

398657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56958.

The product of its digits is 45360, while the sum is 38.

The square root of 398657 is about 631.3929046165. The cubic root of 398657 is about 73.5980766077.

The spelling of 398657 in words is "three hundred ninety-eight thousand, six hundred fifty-seven".