521424 has 80 divisors (see below), whose sum is σ = 1607040. Its totient is φ = 161280.

The previous prime is 521401. The next prime is 521429. The reversal of 521424 is 424125.

521424 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 521397 and 521406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521429) by changing a digit.

521424 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 15 ways as a sum of consecutive naturals, for example, 7309 + ... + 7379.

It is an arithmetic number, because the mean of its divisors is an integer number (20088).

2⁵²¹⁴²⁴ is an apocalyptic number.

521424 is a gapful number since it is divisible by the number (54) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 521424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (803520).

521424 is an abundant number, since it is smaller than the sum of its proper divisors (1085616).

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

521424 is a wasteful number, since it uses less digits than its factorization.

521424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105 (or 93 counting only the distinct ones).

The product of its digits is 320, while the sum is 18.

The square root of 521424 is about 722.0969463999. The cubic root of 521424 is about 80.4878522878.

Adding to 521424 its reverse (424125), we get a palindrome (945549).

The spelling of 521424 in words is "five hundred twenty-one thousand, four hundred twenty-four".