521808 has 40 divisors (see below), whose sum is σ = 1541568. Its totient is φ = 148992.

The previous prime is 521791. The next prime is 521809. The reversal of 521808 is 808125.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 521808.

It is not an unprimeable number, because it can be changed into a prime (521809) by changing a digit.

521808 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 441 + ... + 1112.

2⁵²¹⁸⁰⁸ is an apocalyptic number.

It is an amenable number.

521808 is an abundant number, since it is smaller than the sum of its proper divisors (1019760).

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

521808 is a wasteful number, since it uses less digits than its factorization.

521808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1571 (or 1565 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 24.

The square root of 521808 is about 722.3627897393. The cubic root of 521808 is about 80.5076057266.

The spelling of 521808 in words is "five hundred twenty-one thousand, eight hundred eight".