6544436221 has 2 divisors, whose sum is σ = 6544436222. Its totient is φ = 6544436220.

The previous prime is 6544436219. The next prime is 6544436233. The reversal of 6544436221 is 1226344456.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5835279321 + 709156900 = 76389^2 + 26630^2 .

It is a cyclic number.

It is not a de Polignac number, because 6544436221 - 2¹ = 6544436219 is a prime.

Together with 6544436219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6544436281) 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, 3272218110 + 3272218111.

It is an arithmetic number, because the mean of its divisors is an integer number (3272218111).

Almost surely, 2^6544436221 is an apocalyptic number.

It is an amenable number.

6544436221 is a deficient number, since it is larger than the sum of its proper divisors (1).

6544436221 is an equidigital number, since it uses as much as digits as its factorization.

6544436221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 138240, while the sum is 37.

The square root of 6544436221 is about 80897.6898372259. The cubic root of 6544436221 is about 1870.4987108200.

The spelling of 6544436221 in words is "six billion, five hundred forty-four million, four hundred thirty-six thousand, two hundred twenty-one".