6564705221 has 2 divisors, whose sum is σ = 6564705222. Its totient is φ = 6564705220.

The previous prime is 6564705179. The next prime is 6564705271. The reversal of 6564705221 is 1225074656.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3622836100 + 2941869121 = 60190^2 + 54239^2 .

It is a cyclic number.

It is not a de Polignac number, because 6564705221 - 2¹⁰ = 6564704197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6564705271) 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 as a sum of consecutive naturals, namely, 3282352610 + 3282352611.

It is an arithmetic number, because the mean of its divisors is an integer number (3282352611).

Almost surely, 2^6564705221 is an apocalyptic number.

It is an amenable number.

6564705221 is a deficient number, since it is larger than the sum of its proper divisors (1).

6564705221 is an equidigital number, since it uses as much as digits as its factorization.

6564705221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 100800, while the sum is 38.

The square root of 6564705221 is about 81022.8685063668. The cubic root of 6564705221 is about 1872.4277827624.

Adding to 6564705221 its reverse (1225074656), we get a palindrome (7789779877).

The spelling of 6564705221 in words is "six billion, five hundred sixty-four million, seven hundred five thousand, two hundred twenty-one".