6561656011 has 4 divisors (see below), whose sum is σ = 6621854800. Its totient is φ = 6501457224.

The previous prime is 6561655999. The next prime is 6561656021. The reversal of 6561656011 is 1106561656.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 6561656011 - 2⁵ = 6561655979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6561656021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30099231 + ... + 30099448.

It is an arithmetic number, because the mean of its divisors is an integer number (1655463700).

Almost surely, 2^6561656011 is an apocalyptic number.

6561656011 is a deficient number, since it is larger than the sum of its proper divisors (60198789).

6561656011 is a wasteful number, since it uses less digits than its factorization.

6561656011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60198788.

The product of its (nonzero) digits is 32400, while the sum is 37.

The square root of 6561656011 is about 81004.0493493998. The cubic root of 6561656011 is about 1872.1378327171.

The spelling of 6561656011 in words is "six billion, five hundred sixty-one million, six hundred fifty-six thousand, eleven".