6561244663 has 2 divisors, whose sum is σ = 6561244664. Its totient is φ = 6561244662.

The previous prime is 6561244579. The next prime is 6561244727. The reversal of 6561244663 is 3664421656.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6561244663 - 2²⁵ = 6527690231 is a prime.

It is a super-3 number, since 3×6561244663³ (a number of 30 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6561241663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3280622331 + 3280622332.

It is an arithmetic number, because the mean of its divisors is an integer number (3280622332).

Almost surely, 2^6561244663 is an apocalyptic number.

6561244663 is a deficient number, since it is larger than the sum of its proper divisors (1).

6561244663 is an equidigital number, since it uses as much as digits as its factorization.

6561244663 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 6561244663 is about 81001.5102513527. The cubic root of 6561244663 is about 1872.0987106700.

The spelling of 6561244663 in words is "six billion, five hundred sixty-one million, two hundred forty-four thousand, six hundred sixty-three".