6643656241 has 2 divisors, whose sum is σ = 6643656242. Its totient is φ = 6643656240.

The previous prime is 6643656209. The next prime is 6643656259. The reversal of 6643656241 is 1426563466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5100816400 + 1542839841 = 71420^2 + 39279^2 .

It is a cyclic number.

It is not a de Polignac number, because 6643656241 - 2⁵ = 6643656209 is a prime.

It is not a weakly prime, because it can be changed into another prime (6643656541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3321828120 + 3321828121.

It is an arithmetic number, because the mean of its divisors is an integer number (3321828121).

Almost surely, 2^6643656241 is an apocalyptic number.

It is an amenable number.

6643656241 is a deficient number, since it is larger than the sum of its proper divisors (1).

6643656241 is an equidigital number, since it uses as much as digits as its factorization.

6643656241 is an evil number, because the sum of its binary digits is even.

The product of its digits is 622080, while the sum is 43.

The square root of 6643656241 is about 81508.6267888252. The cubic root of 6643656241 is about 1879.9041977173.

The spelling of 6643656241 in words is "six billion, six hundred forty-three million, six hundred fifty-six thousand, two hundred forty-one".