409685 has 4 divisors (see below), whose sum is σ = 491628. Its totient is φ = 327744.

The previous prime is 409657. The next prime is 409691. The reversal of 409685 is 586904.

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 244036 + 165649 = 494^2 + 407^2 .

It is a cyclic number.

It is not a de Polignac number, because 409685 - 2⁸ = 409429 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 14.

It is a congruent number.

It is an unprimeable number.

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, 40964 + ... + 40973.

It is an arithmetic number, because the mean of its divisors is an integer number (122907).

2⁴⁰⁹⁶⁸⁵ is an apocalyptic number.

It is an amenable number.

409685 is a deficient number, since it is larger than the sum of its proper divisors (81943).

409685 is an equidigital number, since it uses as much as digits as its factorization.

409685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81942.

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

The square root of 409685 is about 640.0664028052. The cubic root of 409685 is about 74.2705581576.

The spelling of 409685 in words is "four hundred nine thousand, six hundred eighty-five".