6543440641 has 16 divisors (see below), whose sum is σ = 7044181200. Its totient is φ = 6056396800.

The previous prime is 6543440597. The next prime is 6543440663. The reversal of 6543440641 is 1460443456.

It can be written as a sum of positive squares in 8 ways, for example, as 30305025 + 6513135616 = 5505^2 + 80704^2 .

It is a cyclic number.

It is not a de Polignac number, because 6543440641 - 2⁷ = 6543440513 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6543440641.

It is not an unprimeable number, because it can be changed into a prime (6543440681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 243045 + ... + 268621.

It is an arithmetic number, because the mean of its divisors is an integer number (440261325).

Almost surely, 2^6543440641 is an apocalyptic number.

It is an amenable number.

6543440641 is a deficient number, since it is larger than the sum of its proper divisors (500740559).

6543440641 is a wasteful number, since it uses less digits than its factorization.

6543440641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25844.

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

The square root of 6543440641 is about 80891.5362754349. The cubic root of 6543440641 is about 1870.4038554098.

The spelling of 6543440641 in words is "six billion, five hundred forty-three million, four hundred forty thousand, six hundred forty-one".