521020240 has 120 divisors (see below), whose sum is σ = 1329524280. Its totient is φ = 189775872.

The previous prime is 521020237. The next prime is 521020259. The reversal of 521020240 is 42020125.

It can be written as a sum of positive squares in 12 ways, for example, as 466732816 + 54287424 = 21604^2 + 7368^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1203064 + ... + 1203496.

It is an arithmetic number, because the mean of its divisors is an integer number (11079369).

Almost surely, 2^521020240 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 521020240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (664762140).

521020240 is an abundant number, since it is smaller than the sum of its proper divisors (808504040).

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

521020240 is a wasteful number, since it uses less digits than its factorization.

521020240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 561 (or 542 counting only the distinct ones).

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

The square root of 521020240 is about 22825.8677819705. The cubic root of 521020240 is about 804.6707190757.

Adding to 521020240 its reverse (42020125), we get a palindrome (563040365).

The spelling of 521020240 in words is "five hundred twenty-one million, twenty thousand, two hundred forty".