6664443221 has 2 divisors, whose sum is σ = 6664443222. Its totient is φ = 6664443220.

The previous prime is 6664443197. The next prime is 6664443259. The reversal of 6664443221 is 1223444666.

It is an a-pointer prime, because the next prime (6664443259) can be obtained adding 6664443221 to its sum of digits (38).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6259024996 + 405418225 = 79114^2 + 20135^2 .

It is a cyclic number.

It is not a de Polignac number, because 6664443221 - 2¹⁸ = 6664181077 is a prime.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6664449221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3332221610 + 3332221611.

It is an arithmetic number, because the mean of its divisors is an integer number (3332221611).

Almost surely, 2^6664443221 is an apocalyptic number.

It is an amenable number.

6664443221 is a deficient number, since it is larger than the sum of its proper divisors (1).

6664443221 is an equidigital number, since it uses as much as digits as its factorization.

6664443221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 165888, while the sum is 38.

The square root of 6664443221 is about 81636.0411889259. The cubic root of 6664443221 is about 1881.8628002486.

Adding to 6664443221 its reverse (1223444666), we get a palindrome (7887887887).

The spelling of 6664443221 in words is "six billion, six hundred sixty-four million, four hundred forty-three thousand, two hundred twenty-one".