666895 has 4 divisors (see below), whose sum is σ = 800280. Its totient is φ = 533512.

The previous prime is 666889. The next prime is 666901. The reversal of 666895 is 598666.

666895 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 598666 = 2 ⋅299333.

It is an interprime number because it is at equal distance from previous prime (666889) and next prime (666901).

It is a cyclic number.

It is not a de Polignac number, because 666895 - 2¹¹ = 664847 is a prime.

It is a congruent 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, 66685 + ... + 66694.

It is an arithmetic number, because the mean of its divisors is an integer number (200070).

2⁶⁶⁶⁸⁹⁵ is an apocalyptic number.

666895 is a deficient number, since it is larger than the sum of its proper divisors (133385).

666895 is a wasteful number, since it uses less digits than its factorization.

666895 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133384.

The product of its digits is 77760, while the sum is 40.

The square root of 666895 is about 816.6363939967. The cubic root of 666895 is about 87.3680187122.

The spelling of 666895 in words is "six hundred sixty-six thousand, eight hundred ninety-five".