521680 has 20 divisors (see below), whose sum is σ = 1213092. Its totient is φ = 208640.

The previous prime is 521671. The next prime is 521693. The reversal of 521680 is 86125.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 355216 + 166464 = 596^2 + 408^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3181 + ... + 3340.

521680 is a Friedman number, since it can be written as 65210*8, using all its digits and the basic arithmetic operations.

2⁵²¹⁶⁸⁰ is an apocalyptic number.

It is an amenable number.

521680 is an abundant number, since it is smaller than the sum of its proper divisors (691412).

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

521680 is a wasteful number, since it uses less digits than its factorization.

521680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6534 (or 6528 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 521680 is about 722.2741861648. The cubic root of 521680 is about 80.5010223241.

The spelling of 521680 in words is "five hundred twenty-one thousand, six hundred eighty".