66668678 has 4 divisors (see below), whose sum is σ = 100003020. Its totient is φ = 33334338.

The previous prime is 66668677. The next prime is 66668683. The reversal of 66668678 is 87686666.

66668678 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87686666 = 2 ⋅43843333.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66668677) 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 as a sum of consecutive naturals, namely, 16667168 + ... + 16667171.

It is an arithmetic number, because the mean of its divisors is an integer number (25000755).

Almost surely, 2^66668678 is an apocalyptic number.

66668678 is a deficient number, since it is larger than the sum of its proper divisors (33334342).

66668678 is a wasteful number, since it uses less digits than its factorization.

66668678 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33334341.

The product of its digits is 3483648, while the sum is 53.

The square root of 66668678 is about 8165.0889768575. The cubic root of 66668678 is about 405.4842107758.

The spelling of 66668678 in words is "sixty-six million, six hundred sixty-eight thousand, six hundred seventy-eight".