6765566521 has 16 divisors (see below), whose sum is σ = 7884057600. Its totient is φ = 5685594768.

The previous prime is 6765566501. The next prime is 6765566527. The reversal of 6765566521 is 1256655676.

It is not a de Polignac number, because 6765566521 - 2⁷ = 6765566393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6765566527) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 134916 + ... + 178138.

It is an arithmetic number, because the mean of its divisors is an integer number (492753600).

Almost surely, 2^6765566521 is an apocalyptic number.

It is an amenable number.

6765566521 is a deficient number, since it is larger than the sum of its proper divisors (1118491079).

6765566521 is a wasteful number, since it uses less digits than its factorization.

6765566521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43668.

The product of its digits is 2268000, while the sum is 49.

The square root of 6765566521 is about 82253.0639003800. The cubic root of 6765566521 is about 1891.3332437487. Note that the first 3 decimals are identical.

The spelling of 6765566521 in words is "six billion, seven hundred sixty-five million, five hundred sixty-six thousand, five hundred twenty-one".