66666668 has 24 divisors (see below), whose sum is σ = 123076800. Its totient is φ = 31509648.

The previous prime is 66666667. The next prime is 66666683. The reversal of 66666668 is 86666666.

66666668 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (50) coincides with the sum of the digits of its prime factors.

It is a plaindrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (66666667) 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, 55571 + ... + 56757.

It is an arithmetic number, because the mean of its divisors is an integer number (5128200).

Almost surely, 2^66666668 is an apocalyptic number.

It is an amenable number.

66666668 is a deficient number, since it is larger than the sum of its proper divisors (56410132).

66666668 is a wasteful number, since it uses less digits than its factorization.

66666668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1949 (or 1947 counting only the distinct ones).

The product of its digits is 2239488, while the sum is 50.

The square root of 66666668 is about 8164.9658909269. The cubic root of 66666668 is about 405.4801357414.

The spelling of 66666668 in words is "sixty-six million, six hundred sixty-six thousand, six hundred sixty-eight".