521220 has 96 divisors (see below), whose sum is σ = 1790208. Its totient is φ = 110592.

The previous prime is 521201. The next prime is 521231. The reversal of 521220 is 22125.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 521196 and 521205.

It is a congruent number.

It is an unprimeable number.

521220 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7104 + ... + 7176.

It is an arithmetic number, because the mean of its divisors is an integer number (18648).

2⁵²¹²²⁰ 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 521220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (895104).

521220 is an abundant number, since it is smaller than the sum of its proper divisors (1268988).

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

521220 is a wasteful number, since it uses less digits than its factorization.

521220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109 (or 107 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 12.

The square root of 521220 is about 721.9556773099. The cubic root of 521220 is about 80.4773543286.

Adding to 521220 its reverse (22125), we get a palindrome (543345).

It can be divided in two parts, 521 and 220, that added together give a triangular number (741 = T₃₈).

The spelling of 521220 in words is "five hundred twenty-one thousand, two hundred twenty".