6501566561 has 16 divisors (see below), whose sum is σ = 7788232704. Its totient is φ = 5306544144.

The previous prime is 6501566557. The next prime is 6501566567. The reversal of 6501566561 is 1656651056.

It is a cyclic number.

It is not a de Polignac number, because 6501566561 - 2² = 6501566557 is a prime.

It is a super-2 number, since 2×6501566561² = 84540735494226733442, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (6501566567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54641 + ... + 126446.

It is an arithmetic number, because the mean of its divisors is an integer number (486764544).

Almost surely, 2^6501566561 is an apocalyptic number.

It is an amenable number.

6501566561 is a deficient number, since it is larger than the sum of its proper divisors (1286666143).

6501566561 is a wasteful number, since it uses less digits than its factorization.

6501566561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181340.

The product of its (nonzero) digits is 162000, while the sum is 41.

The square root of 6501566561 is about 80632.2922965731. The cubic root of 6501566561 is about 1866.4054947350.

The spelling of 6501566561 in words is "six billion, five hundred one million, five hundred sixty-six thousand, five hundred sixty-one".