163865 has 8 divisors (see below), whose sum is σ = 211848. Its totient is φ = 120960.

The previous prime is 163861. The next prime is 163871. The reversal of 163865 is 568361.

It can be written as a sum of positive squares in 4 ways, for example, as 10201 + 153664 = 101^2 + 392^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 163865 - 2² = 163861 is a prime.

It is not an unprimeable number, because it can be changed into a prime (163861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1196 + ... + 1325.

It is an arithmetic number, because the mean of its divisors is an integer number (26481).

2¹⁶³⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

163865 is a deficient number, since it is larger than the sum of its proper divisors (47983).

163865 is a wasteful number, since it uses less digits than its factorization.

163865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2539.

The product of its digits is 4320, while the sum is 29.

The square root of 163865 is about 404.8024209414. The cubic root of 163865 is about 54.7220133161.

Subtracting 163865 from its reverse (568361), we obtain a square (404496 = 636²).

The spelling of 163865 in words is "one hundred sixty-three thousand, eight hundred sixty-five".