521440 has 24 divisors (see below), whose sum is σ = 1232280. Its totient is φ = 208512.

The previous prime is 521429. The next prime is 521447. The reversal of 521440 is 44125.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521447) 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 3 ways as a sum of consecutive naturals, for example, 1470 + ... + 1789.

It is an arithmetic number, because the mean of its divisors is an integer number (51345).

2⁵²¹⁴⁴⁰ is an apocalyptic number.

It is an amenable number.

521440 is an abundant number, since it is smaller than the sum of its proper divisors (710840).

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

521440 is a wasteful number, since it uses less digits than its factorization.

521440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3274 (or 3266 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 521440 is about 722.1080251597. The cubic root of 521440 is about 80.4886755414.

Adding to 521440 its reverse (44125), we get a palindrome (565565).

It can be divided in two parts, 521 and 440, that added together give a square (961 = 31²).

The spelling of 521440 in words is "five hundred twenty-one thousand, four hundred forty".