398905 has 24 divisors (see below), whose sum is σ = 576072. Its totient is φ = 262656.

The previous prime is 398903. The next prime is 398917. The reversal of 398905 is 509893.

It can be written as a sum of positive squares in 4 ways, for example, as 29241 + 369664 = 171^2 + 608^2 .

It is not a de Polignac number, because 398905 - 2¹ = 398903 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (398903) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20986 + ... + 21004.

It is an arithmetic number, because the mean of its divisors is an integer number (24003).

2³⁹⁸⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

398905 is a deficient number, since it is larger than the sum of its proper divisors (177167).

398905 is a wasteful number, since it uses less digits than its factorization.

398905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73 (or 54 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 34.

The square root of 398905 is about 631.5892652666. The cubic root of 398905 is about 73.6133349538.

The spelling of 398905 in words is "three hundred ninety-eight thousand, nine hundred five".