666920 has 16 divisors (see below), whose sum is σ = 1500660. Its totient is φ = 266752.

The previous prime is 666901. The next prime is 666929. The reversal of 666920 is 29666.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 643204 + 23716 = 802^2 + 154^2 .

It is not an unprimeable number, because it can be changed into a prime (666929) by changing a digit.

666920 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8297 + ... + 8376.

2⁶⁶⁶⁹²⁰ is an apocalyptic number.

It is an amenable number.

666920 is an abundant number, since it is smaller than the sum of its proper divisors (833740).

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

666920 is a wasteful number, since it uses less digits than its factorization.

666920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16684 (or 16680 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 29.

The square root of 666920 is about 816.6517005431. The cubic root of 666920 is about 87.3691104249.

The spelling of 666920 in words is "six hundred sixty-six thousand, nine hundred twenty".