520405 has 16 divisors (see below), whose sum is σ = 670320. Its totient is φ = 387072.

The previous prime is 520393. The next prime is 520409. The reversal of 520405 is 504025.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 10609 + 509796 = 103^2 + 714^2 .

It is a cyclic number.

It is not a de Polignac number, because 520405 - 2¹⁵ = 487637 is a prime.

520405 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (520409) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5317 + ... + 5413.

It is an arithmetic number, because the mean of its divisors is an integer number (41895).

2⁵²⁰⁴⁰⁵ is an apocalyptic number.

It is an amenable number.

520405 is a deficient number, since it is larger than the sum of its proper divisors (149915).

520405 is a wasteful number, since it uses less digits than its factorization.

520405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168.

The product of its (nonzero) digits is 200, while the sum is 16.

The square root of 520405 is about 721.3910174101. The cubic root of 520405 is about 80.4353865995.

The spelling of 520405 in words is "five hundred twenty thousand, four hundred five".