27806566861 has 24 divisors (see below), whose sum is σ = 29799686400. Its totient is φ = 25938675360.

The previous prime is 27806566849. The next prime is 27806566883. The reversal of 27806566861 is 16866560872.

It is not a de Polignac number, because 27806566861 - 2²¹ = 27804469709 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27806566831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12518731 + ... + 12520951.

It is an arithmetic number, because the mean of its divisors is an integer number (1241653600).

Almost surely, 2^27806566861 is an apocalyptic number.

It is an amenable number.

27806566861 is a deficient number, since it is larger than the sum of its proper divisors (1993119539).

27806566861 is a wasteful number, since it uses less digits than its factorization.

27806566861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2777 (or 2758 counting only the distinct ones).

The product of its (nonzero) digits is 5806080, while the sum is 55.

The spelling of 27806566861 in words is "twenty-seven billion, eight hundred six million, five hundred sixty-six thousand, eight hundred sixty-one".