666217028 has 6 divisors (see below), whose sum is σ = 1165879806. Its totient is φ = 333108512.

The previous prime is 666217021. The next prime is 666217037. The reversal of 666217028 is 820712666.

It is a happy number.

666217028 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 656281924 + 9935104 = 25618^2 + 3152^2 .

It is a junction number, because it is equal to n+sod(n) for n = 666216982 and 666217000.

It is not an unprimeable number, because it can be changed into a prime (666217021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83277125 + ... + 83277132.

It is an arithmetic number, because the mean of its divisors is an integer number (194313301).

Almost surely, 2^666217028 is an apocalyptic number.

It is an amenable number.

666217028 is a deficient number, since it is larger than the sum of its proper divisors (499662778).

666217028 is a wasteful number, since it uses less digits than its factorization.

666217028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166554261 (or 166554259 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 38.

The square root of 666217028 is about 25811.1802907190. The cubic root of 666217028 is about 873.3840227880.

The spelling of 666217028 in words is "six hundred sixty-six million, two hundred seventeen thousand, twenty-eight".