805556666 has 16 divisors (see below), whose sum is σ = 1224193824. Its totient is φ = 397502544.

The previous prime is 805556663. The next prime is 805556707. The reversal of 805556666 is 666655508.

It is a self number, because there is not a number n which added to its sum of digits gives 805556666.

It is not an unprimeable number, because it can be changed into a prime (805556663) 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 7 ways as a sum of consecutive naturals, for example, 203381 + ... + 207303.

It is an arithmetic number, because the mean of its divisors is an integer number (76512114).

Almost surely, 2^805556666 is an apocalyptic number.

805556666 is a deficient number, since it is larger than the sum of its proper divisors (418637158).

805556666 is a wasteful number, since it uses less digits than its factorization.

805556666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5245.

The product of its (nonzero) digits is 1296000, while the sum is 47.

The square root of 805556666 is about 28382.3301721335. The cubic root of 805556666 is about 930.4621228180.

The spelling of 805556666 in words is "eight hundred five million, five hundred fifty-six thousand, six hundred sixty-six".