78566666 has 16 divisors (see below), whose sum is σ = 123185664. Its totient is φ = 37510704.

The previous prime is 78566647. The next prime is 78566669. The reversal of 78566666 is 66666587.

It is not an unprimeable number, because it can be changed into a prime (78566669) 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, 35591 + ... + 37733.

It is an arithmetic number, because the mean of its divisors is an integer number (7699104).

Almost surely, 2^78566666 is an apocalyptic number.

78566666 is a deficient number, since it is larger than the sum of its proper divisors (44618998).

78566666 is a wasteful number, since it uses less digits than its factorization.

78566666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2965.

The product of its digits is 2177280, while the sum is 50.

The square root of 78566666 is about 8863.7839549484. The cubic root of 78566666 is about 428.2980607889.

The spelling of 78566666 in words is "seventy-eight million, five hundred sixty-six thousand, six hundred sixty-six".