521520 has 80 divisors (see below), whose sum is σ = 1687392. Its totient is φ = 133120.

The previous prime is 521519. The next prime is 521527. The reversal of 521520 is 25125.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×521520² = 543966220800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 521520.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521527) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 9814 + ... + 9866.

2⁵²¹⁵²⁰ 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 521520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (843696).

521520 is an abundant number, since it is smaller than the sum of its proper divisors (1165872).

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

521520 is a wasteful number, since it uses less digits than its factorization.

521520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110 (or 104 counting only the distinct ones).

The product of its (nonzero) digits is 100, while the sum is 15.

The square root of 521520 is about 722.1634164093. The cubic root of 521520 is about 80.4927915565.

Adding to 521520 its reverse (25125), we get a palindrome (546645).

The spelling of 521520 in words is "five hundred twenty-one thousand, five hundred twenty".