666870 has 16 divisors (see below), whose sum is σ = 1600560. Its totient is φ = 177824.

The previous prime is 666857. The next prime is 666871. The reversal of 666870 is 78666.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11085 + ... + 11144.

It is an arithmetic number, because the mean of its divisors is an integer number (100035).

2⁶⁶⁶⁸⁷⁰ is an apocalyptic number.

666870 is an abundant number, since it is smaller than the sum of its proper divisors (933690).

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

666870 is a wasteful number, since it uses less digits than its factorization.

666870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22239.

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 666870 is about 816.6210871634. The cubic root of 666870 is about 87.3669269722.

The spelling of 666870 in words is "six hundred sixty-six thousand, eight hundred seventy".