398521 has 4 divisors (see below), whose sum is σ = 415872. Its totient is φ = 381172.

The previous prime is 398509. The next prime is 398539. The reversal of 398521 is 125893.

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: 125893 = 67 ⋅1879.

It is a cyclic number.

It is not a de Polignac number, because 398521 - 2⁷ = 398393 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 398521.

It is not an unprimeable number, because it can be changed into a prime (398581) 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, 8641 + ... + 8686.

It is an arithmetic number, because the mean of its divisors is an integer number (103968).

2³⁹⁸⁵²¹ is an apocalyptic number.

It is an amenable number.

398521 is a deficient number, since it is larger than the sum of its proper divisors (17351).

398521 is a wasteful number, since it uses less digits than its factorization.

398521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17350.

The product of its digits is 2160, while the sum is 28.

The square root of 398521 is about 631.2851970385. The cubic root of 398521 is about 73.5897064409.

It can be divided in two parts, 398 and 521, that added together give a palindrome (919).

The spelling of 398521 in words is "three hundred ninety-eight thousand, five hundred twenty-one".