520905 has 48 divisors (see below), whose sum is σ = 1072512. Its totient is φ = 211200.

The previous prime is 520889. The next prime is 520913. The reversal of 520905 is 509025.

It is not a de Polignac number, because 520905 - 2⁴ = 520889 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 12685 + ... + 12725.

It is an arithmetic number, because the mean of its divisors is an integer number (22344).

2⁵²⁰⁹⁰⁵ is an apocalyptic number.

520905 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

It is an amenable number.

520905 is an abundant number, since it is smaller than the sum of its proper divisors (551607).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

520905 is a wasteful number, since it uses less digits than its factorization.

520905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78 (or 67 counting only the distinct ones).

The product of its (nonzero) digits is 450, while the sum is 21.

The square root of 520905 is about 721.7374869023. The cubic root of 520905 is about 80.4611388629.

It can be divided in two parts, 5 and 20905, that added together give a triangular number (20910 = T₂₀₄).

The spelling of 520905 in words is "five hundred twenty thousand, nine hundred five".