521521321 has 2 divisors, whose sum is σ = 521521322. Its totient is φ = 521521320.

The previous prime is 521521303. The next prime is 521521331. The reversal of 521521321 is 123125125.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 423906921 + 97614400 = 20589^2 + 9880^2 .

It is a cyclic number.

It is not a de Polignac number, because 521521321 - 2⁵ = 521521289 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 521521292 and 521521301.

It is not a weakly prime, because it can be changed into another prime (521521331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260760660 + 260760661.

It is an arithmetic number, because the mean of its divisors is an integer number (260760661).

Almost surely, 2^521521321 is an apocalyptic number.

It is an amenable number.

521521321 is a deficient number, since it is larger than the sum of its proper divisors (1).

521521321 is an equidigital number, since it uses as much as digits as its factorization.

521521321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 600, while the sum is 22.

The square root of 521521321 is about 22836.8413096032. The cubic root of 521521321 is about 804.9285951865.

Adding to 521521321 its reverse (123125125), we get a palindrome (644646446).

The spelling of 521521321 in words is "five hundred twenty-one million, five hundred twenty-one thousand, three hundred twenty-one".