666945 has 12 divisors (see below), whose sum is σ = 1156116. Its totient is φ = 355680.

The previous prime is 666937. The next prime is 666959. The reversal of 666945 is 549666.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 266256 + 400689 = 516^2 + 633^2 .

It is not a de Polignac number, because 666945 - 2³ = 666937 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7366 + ... + 7455.

It is an arithmetic number, because the mean of its divisors is an integer number (96343).

2⁶⁶⁶⁹⁴⁵ is an apocalyptic number.

It is an amenable number.

666945 is a deficient number, since it is larger than the sum of its proper divisors (489171).

666945 is a wasteful number, since it uses less digits than its factorization.

666945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14832 (or 14829 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 666945 is about 816.6670068027. The cubic root of 666945 is about 87.3702021103.

The spelling of 666945 in words is "six hundred sixty-six thousand, nine hundred forty-five".