521720004 has 48 divisors (see below), whose sum is σ = 1388112768. Its totient is φ = 151085568.

The previous prime is 521719997. The next prime is 521720033. The reversal of 521720004 is 400027125.

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 15 ways as a sum of consecutive naturals, for example, 95712 + ... + 101015.

It is an arithmetic number, because the mean of its divisors is an integer number (28919016).

Almost surely, 2^521720004 is an apocalyptic number.

It is an amenable number.

521720004 is an abundant number, since it is smaller than the sum of its proper divisors (866392764).

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

521720004 is a wasteful number, since it uses less digits than its factorization.

521720004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196764 (or 196762 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 21.

The square root of 521720004 is about 22841.1909496856. The cubic root of 521720004 is about 805.0307995880.

Adding to 521720004 its reverse (400027125), we get a palindrome (921747129).

The spelling of 521720004 in words is "five hundred twenty-one million, seven hundred twenty thousand, four".