520315021 has 4 divisors (see below), whose sum is σ = 522956412. Its totient is φ = 517673632.

The previous prime is 520315001. The next prime is 520315031. The reversal of 520315021 is 120513025.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 384708996 + 135606025 = 19614^2 + 11645^2 .

It is a cyclic number.

It is not a de Polignac number, because 520315021 - 2⁵ = 520314989 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 520315021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (520315001) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1320400 + ... + 1320793.

It is an arithmetic number, because the mean of its divisors is an integer number (130739103).

Almost surely, 2^520315021 is an apocalyptic number.

It is an amenable number.

520315021 is a deficient number, since it is larger than the sum of its proper divisors (2641391).

520315021 is a wasteful number, since it uses less digits than its factorization.

520315021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2641390.

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 520315021 is about 22810.4147485310. The cubic root of 520315021 is about 804.3075052255.

Adding to 520315021 its reverse (120513025), we get a palindrome (640828046).

The spelling of 520315021 in words is "five hundred twenty million, three hundred fifteen thousand, twenty-one".