666885 has 16 divisors (see below), whose sum is σ = 1113984. Its totient is φ = 340032.

The previous prime is 666871. The next prime is 666889. The reversal of 666885 is 588666.

It is not a de Polignac number, because 666885 - 2⁶ = 666821 is a prime.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666889) 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, 622 + ... + 1311.

It is an arithmetic number, because the mean of its divisors is an integer number (69624).

2⁶⁶⁶⁸⁸⁵ is an apocalyptic number.

It is an amenable number.

666885 is a deficient number, since it is larger than the sum of its proper divisors (447099).

666885 is a wasteful number, since it uses less digits than its factorization.

666885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1964.

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

The square root of 666885 is about 816.6302712978. The cubic root of 666885 is about 87.3675820195.

It can be divided in two parts, 666 and 885, that added together give a palindrome (1551).

The spelling of 666885 in words is "six hundred sixty-six thousand, eight hundred eighty-five".