858666 has 8 divisors (see below), whose sum is σ = 1717344. Its totient is φ = 286220.

The previous prime is 858631. The next prime is 858673. The reversal of 858666 is 666858.

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

858666 is an admirable number.

It is an Ulam number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 71550 + ... + 71561.

It is an arithmetic number, because the mean of its divisors is an integer number (214668).

2⁸⁵⁸⁶⁶⁶ is an apocalyptic number.

858666 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.

858666 is a wasteful number, since it uses less digits than its factorization.

858666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143116.

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

The square root of 858666 is about 926.6423258194. The cubic root of 858666 is about 95.0476584511.

Adding to 858666 its sum of digits (39), we get a triangular number (858705 = T₁₃₁₀).

The spelling of 858666 in words is "eight hundred fifty-eight thousand, six hundred sixty-six".