668686478 has 16 divisors (see below), whose sum is σ = 1024799040. Its totient is φ = 327122016.

The previous prime is 668686477. The next prime is 668686489. The reversal of 668686478 is 874686866.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668686477) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30308 + ... + 47496.

It is an arithmetic number, because the mean of its divisors is an integer number (64049940).

Almost surely, 2^668686478 is an apocalyptic number.

668686478 is a deficient number, since it is larger than the sum of its proper divisors (356112562).

668686478 is a wasteful number, since it uses less digits than its factorization.

668686478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17611.

The product of its digits is 18579456, while the sum is 59.

The square root of 668686478 is about 25858.9728720999. The cubic root of 668686478 is about 874.4618091216.

The spelling of 668686478 in words is "six hundred sixty-eight million, six hundred eighty-six thousand, four hundred seventy-eight".