666807 has 4 divisors (see below), whose sum is σ = 889080. Its totient is φ = 444536.

The previous prime is 666773. The next prime is 666811. The reversal of 666807 is 708666.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 666807 - 2¹⁰ = 665783 is a prime.

It is an Ulam number.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666857) 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 3 ways as a sum of consecutive naturals, for example, 111132 + ... + 111137.

It is an arithmetic number, because the mean of its divisors is an integer number (222270).

2⁶⁶⁶⁸⁰⁷ is an apocalyptic number.

666807 is a deficient number, since it is larger than the sum of its proper divisors (222273).

666807 is a wasteful number, since it uses less digits than its factorization.

666807 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222272.

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

The square root of 666807 is about 816.5825126709. The cubic root of 666807 is about 87.3641756665.

The spelling of 666807 in words is "six hundred sixty-six thousand, eight hundred seven".