520404221 has 8 divisors (see below), whose sum is σ = 551328120. Its totient is φ = 489515008.

The previous prime is 520404169. The next prime is 520404229. The reversal of 520404221 is 122404025.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 62500 + 520341721 = 250^2 + 22811^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-520404221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 520404193 and 520404202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (520404229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26285 + ... + 41613.

It is an arithmetic number, because the mean of its divisors is an integer number (68916015).

Almost surely, 2^520404221 is an apocalyptic number.

It is an amenable number.

520404221 is a deficient number, since it is larger than the sum of its proper divisors (30923899).

520404221 is a wasteful number, since it uses less digits than its factorization.

520404221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17343.

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 520404221 is about 22812.3699119579. The cubic root of 520404221 is about 804.3534646457.

Adding to 520404221 its reverse (122404025), we get a palindrome (642808246).

The spelling of 520404221 in words is "five hundred twenty million, four hundred four thousand, two hundred twenty-one".