505405 has 4 divisors (see below), whose sum is σ = 606492. Its totient is φ = 404320.

The previous prime is 505399. The next prime is 505409. The reversal of 505405 is 504505.

It is a happy number.

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 356409 + 148996 = 597^2 + 386^2 .

It is not a de Polignac number, because 505405 - 2⁷ = 505277 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (505409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 50536 + ... + 50545.

It is an arithmetic number, because the mean of its divisors is an integer number (151623).

2⁵⁰⁵⁴⁰⁵ is an apocalyptic number.

It is an amenable number.

505405 is a deficient number, since it is larger than the sum of its proper divisors (101087).

505405 is a wasteful number, since it uses less digits than its factorization.

505405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101086.

The product of its (nonzero) digits is 500, while the sum is 19.

The square root of 505405 is about 710.9184200736. The cubic root of 505405 is about 79.6550249577.

Subtracting from 505405 its reverse (504505), we obtain a square (900 = 30²).

The spelling of 505405 in words is "five hundred five thousand, four hundred five".