409905 has 12 divisors (see below), whose sum is σ = 710580. Its totient is φ = 218592.

The previous prime is 409901. The next prime is 409909. The reversal of 409905 is 509904.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (409901) and next prime (409909).

It can be written as a sum of positive squares in 2 ways, for example, as 91809 + 318096 = 303^2 + 564^2 .

It is not a de Polignac number, because 409905 - 2² = 409901 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (409901) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 4510 + ... + 4599.

It is an arithmetic number, because the mean of its divisors is an integer number (59215).

2⁴⁰⁹⁹⁰⁵ is an apocalyptic number.

409905 is a gapful number since it is divisible by the number (45) formed by its first and last digit.

It is an amenable number.

409905 is a deficient number, since it is larger than the sum of its proper divisors (300675).

409905 is a wasteful number, since it uses less digits than its factorization.

409905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9120 (or 9117 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 409905 is about 640.2382369087. The cubic root of 409905 is about 74.2838501575.

Subtracting 409905 from its reverse (509904), we obtain a palindrome (99999).

The spelling of 409905 in words is "four hundred nine thousand, nine hundred five".