666858 has 8 divisors (see below), whose sum is σ = 1333728. Its totient is φ = 222284.

The previous prime is 666857. The next prime is 666871. The reversal of 666858 is 858666.

666858 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

666858 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (666857) 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, 55566 + ... + 55577.

It is an arithmetic number, because the mean of its divisors is an integer number (166716).

2⁶⁶⁶⁸⁵⁸ is an apocalyptic number.

666858 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

666858 is a wasteful number, since it uses less digits than its factorization.

666858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111148.

The product of its digits is 69120, while the sum is 39.

The square root of 666858 is about 816.6137397815. The cubic root of 666858 is about 87.3664029274.

The spelling of 666858 in words is "six hundred sixty-six thousand, eight hundred fifty-eight".