666868686 has 32 divisors (see below), whose sum is σ = 1494315648. Its totient is φ = 196619040.

The previous prime is 666868667. The next prime is 666868687. The reversal of 666868686 is 686868666.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666868687) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 134100 + ... + 138983.

It is an arithmetic number, because the mean of its divisors is an integer number (46697364).

Almost surely, 2^666868686 is an apocalyptic number.

666868686 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

666868686 is an abundant number, since it is smaller than the sum of its proper divisors (827446962).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

666868686 is a wasteful number, since it uses less digits than its factorization.

666868686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 273136.

The product of its digits is 23887872, while the sum is 60.

The square root of 666868686 is about 25823.8007659601. The cubic root of 666868686 is about 873.6686958962.

The spelling of 666868686 in words is "six hundred sixty-six million, eight hundred sixty-eight thousand, six hundred eighty-six".