66878979 has 8 divisors (see below), whose sum is σ = 91069440. Its totient is φ = 43637256.

The previous prime is 66878971. The next prime is 66878983. The reversal of 66878979 is 97987866.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66878979 - 2³ = 66878971 is a prime.

It is a zygodrome in base 2.

It is not an unprimeable number, because it can be changed into a prime (66878971) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 237019 + ... + 237300.

It is an arithmetic number, because the mean of its divisors is an integer number (11383680).

Almost surely, 2^66878979 is an apocalyptic number.

66878979 is a deficient number, since it is larger than the sum of its proper divisors (24190461).

66878979 is a wasteful number, since it uses less digits than its factorization.

66878979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 474369.

The product of its digits is 9144576, while the sum is 60.

The square root of 66878979 is about 8177.9568964381. The cubic root of 66878979 is about 405.9101190699.

The spelling of 66878979 in words is "sixty-six million, eight hundred seventy-eight thousand, nine hundred seventy-nine".