520640 has 28 divisors (see below), whose sum is σ = 1240536. Its totient is φ = 208128.

The previous prime is 520633. The next prime is 520649. The reversal of 520640 is 46025.

520640 is nontrivially palindromic in base 3.

It is a zygodrome in base 2 and base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (520649) by changing a digit.

520640 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 494 + ... + 1133.

2⁵²⁰⁶⁴⁰ is an apocalyptic number.

It is an amenable number.

520640 is an abundant number, since it is smaller than the sum of its proper divisors (719896).

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

520640 is a wasteful number, since it uses less digits than its factorization.

520640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1644 (or 1634 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 520640 is about 721.5538787922. The cubic root of 520640 is about 80.4474922168.

Adding to 520640 its reverse (46025), we get a palindrome (566665).

The spelling of 520640 in words is "five hundred twenty thousand, six hundred forty".