521808125 has 10 divisors (see below), whose sum is σ = 652052214. Its totient is φ = 417446000.

The previous prime is 521808121. The next prime is 521808137.

It is a happy number.

521808125 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 5 ways, for example, as 149279524 + 372528601 = 12218^2 + 19301^2 .

It is not a de Polignac number, because 521808125 - 2² = 521808121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 521808091 and 521808100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521808121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 416822 + ... + 418071.

Almost surely, 2^521808125 is an apocalyptic number.

It is an amenable number.

521808125 is a deficient number, since it is larger than the sum of its proper divisors (130244089).

521808125 is an frugal number, since it uses more digits than its factorization.

521808125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 834913 (or 834898 counting only the distinct ones).

The product of its (nonzero) digits is 6400, while the sum is 32.

The square root of 521808125 is about 22843.1198613499. The cubic root of 521808125 is about 805.0761215518.

The spelling of 521808125 in words is "five hundred twenty-one million, eight hundred eight thousand, one hundred twenty-five".