6656656081 has 4 divisors (see below), whose sum is σ = 6657044464. Its totient is φ = 6656267700.

The previous prime is 6656656079. The next prime is 6656656091. The reversal of 6656656081 is 1806566566.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 6656656081 - 2¹ = 6656656079 is a prime.

It is a super-2 number, since 2×6656656081² = 88622140361428557122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6656656091) 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 3 ways as a sum of consecutive naturals, for example, 167235 + ... + 203176.

It is an arithmetic number, because the mean of its divisors is an integer number (1664261116).

Almost surely, 2^6656656081 is an apocalyptic number.

It is an amenable number.

6656656081 is a deficient number, since it is larger than the sum of its proper divisors (388383).

6656656081 is a wasteful number, since it uses less digits than its factorization.

6656656081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 388382.

The product of its (nonzero) digits is 1555200, while the sum is 49.

The square root of 6656656081 is about 81588.3329955944. The cubic root of 6656656081 is about 1881.1295536754.

The spelling of 6656656081 in words is "six billion, six hundred fifty-six million, six hundred fifty-six thousand, eighty-one".