521840404 has 6 divisors (see below), whose sum is σ = 913220714. Its totient is φ = 260920200.

The previous prime is 521840387. The next prime is 521840411. The reversal of 521840404 is 404048125.

It can be written as a sum of positive squares in only one way, i.e., 388484100 + 133356304 = 19710^2 + 11548^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65230047 + ... + 65230054.

Almost surely, 2^521840404 is an apocalyptic number.

It is an amenable number.

521840404 is a deficient number, since it is larger than the sum of its proper divisors (391380310).

521840404 is a wasteful number, since it uses less digits than its factorization.

521840404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130460105 (or 130460103 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 28.

The square root of 521840404 is about 22843.8263870132. The cubic root of 521840404 is about 805.0927218531.

Adding to 521840404 its reverse (404048125), we get a palindrome (925888529).

The spelling of 521840404 in words is "five hundred twenty-one million, eight hundred forty thousand, four hundred four".