409865 has 4 divisors (see below), whose sum is σ = 491844. Its totient is φ = 327888.

The previous prime is 409861. The next prime is 409867. The reversal of 409865 is 568904.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 109561 + 300304 = 331^2 + 548^2 .

It is a cyclic number.

It is not a de Polignac number, because 409865 - 2² = 409861 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (409861) 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, 40982 + ... + 40991.

It is an arithmetic number, because the mean of its divisors is an integer number (122961).

2⁴⁰⁹⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

409865 is a deficient number, since it is larger than the sum of its proper divisors (81979).

409865 is an equidigital number, since it uses as much as digits as its factorization.

409865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81978.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 409865 is about 640.2069977749. The cubic root of 409865 is about 74.2814337841.

The spelling of 409865 in words is "four hundred nine thousand, eight hundred sixty-five".