6561440566 has 8 divisors (see below), whose sum is σ = 9863698680. Its totient is φ = 3273541008.

The previous prime is 6561440533. The next prime is 6561440579. The reversal of 6561440566 is 6650441656.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 3588496 + ... + 3590323.

It is an arithmetic number, because the mean of its divisors is an integer number (1232962335).

Almost surely, 2^6561440566 is an apocalyptic number.

6561440566 is a deficient number, since it is larger than the sum of its proper divisors (3302258114).

6561440566 is a wasteful number, since it uses less digits than its factorization.

6561440566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7179278.

The product of its (nonzero) digits is 518400, while the sum is 43.

The square root of 6561440566 is about 81002.7194975576. The cubic root of 6561440566 is about 1872.1173426076.

The spelling of 6561440566 in words is "six billion, five hundred sixty-one million, four hundred forty thousand, five hundred sixty-six".