521904 has 40 divisors (see below), whose sum is σ = 1374912. Its totient is φ = 170560.

The previous prime is 521903. The next prime is 521923. The reversal of 521904 is 409125.

It is a hoax number, since the sum of its digits (21) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (521903) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3919 + ... + 4049.

2⁵²¹⁹⁰⁴ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 521904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (687456).

521904 is an abundant number, since it is smaller than the sum of its proper divisors (853008).

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

521904 is a wasteful number, since it uses less digits than its factorization.

521904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 225 (or 219 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 521904 is about 722.4292352888. The cubic root of 521904 is about 80.5125425720.

The spelling of 521904 in words is "five hundred twenty-one thousand, nine hundred four".