531664020221 has 2 divisors, whose sum is σ = 531664020222. Its totient is φ = 531664020220.

The previous prime is 531664020179. The next prime is 531664020229. The reversal of 531664020221 is 122020466135.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 529818028996 + 1845991225 = 727886^2 + 42965^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-531664020221 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (531664020229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 265832010110 + 265832010111.

It is an arithmetic number, because the mean of its divisors is an integer number (265832010111).

Almost surely, 2^531664020221 is an apocalyptic number.

It is an amenable number.

531664020221 is a deficient number, since it is larger than the sum of its proper divisors (1).

531664020221 is an equidigital number, since it uses as much as digits as its factorization.

531664020221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17280, while the sum is 32.

Adding to 531664020221 its reverse (122020466135), we get a palindrome (653684486356).

The spelling of 531664020221 in words is "five hundred thirty-one billion, six hundred sixty-four million, twenty thousand, two hundred twenty-one".