520868821 has 12 divisors (see below), whose sum is σ = 573252876. Its totient is φ = 472915520.

The previous prime is 520868809. The next prime is 520868857. The reversal of 520868821 is 128868025.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 72488196 + 448380625 = 8514^2 + 21175^2 .

It is not a de Polignac number, because 520868821 - 2⁷ = 520868693 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (520868801) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 113055 + ... + 117571.

It is an arithmetic number, because the mean of its divisors is an integer number (47771073).

Almost surely, 2^520868821 is an apocalyptic number.

It is an amenable number.

520868821 is a deficient number, since it is larger than the sum of its proper divisors (52384055).

520868821 is a wasteful number, since it uses less digits than its factorization.

520868821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5492 (or 5481 counting only the distinct ones).

The product of its (nonzero) digits is 61440, while the sum is 40.

The square root of 520868821 is about 22822.5507119603. The cubic root of 520868821 is about 804.5927603379.

The spelling of 520868821 in words is "five hundred twenty million, eight hundred sixty-eight thousand, eight hundred twenty-one".