521313920 has 64 divisors (see below), whose sum is σ = 1252060200. Its totient is φ = 207556608.

The previous prime is 521313917. The next prime is 521313931. The reversal of 521313920 is 29313125.

521313920 = 410² + 411² + ... + 1177².

It can be written as a sum of positive squares in 4 ways, for example, as 435640384 + 85673536 = 20872^2 + 9256^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is a self number, because there is not a number n which added to its sum of digits gives 521313920.

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 7 ways as a sum of consecutive naturals, for example, 144782 + ... + 148338.

Almost surely, 2^521313920 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 521313920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (626030100).

521313920 is an abundant number, since it is smaller than the sum of its proper divisors (730746280).

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

521313920 is a wasteful number, since it uses less digits than its factorization.

521313920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3805 (or 3793 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 26.

The square root of 521313920 is about 22832.2999279529. The cubic root of 521313920 is about 804.8218784688.

The spelling of 521313920 in words is "five hundred twenty-one million, three hundred thirteen thousand, nine hundred twenty".