66918679 has 4 divisors (see below), whose sum is σ = 66936240. Its totient is φ = 66901120.

The previous prime is 66918673. The next prime is 66918721. The reversal of 66918679 is 97681966.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66918679 - 2³ = 66918671 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 (66918671) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 394 + ... + 11575.

It is an arithmetic number, because the mean of its divisors is an integer number (16734060).

Almost surely, 2^66918679 is an apocalyptic number.

66918679 is a deficient number, since it is larger than the sum of its proper divisors (17561).

66918679 is a wasteful number, since it uses less digits than its factorization.

66918679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17560.

The product of its digits is 979776, while the sum is 52.

The square root of 66918679 is about 8180.3837929525. The cubic root of 66918679 is about 405.9904205558.

The spelling of 66918679 in words is "sixty-six million, nine hundred eighteen thousand, six hundred seventy-nine".