666828 has 18 divisors (see below), whose sum is σ = 1685684. Its totient is φ = 222264.

The previous prime is 666823. The next prime is 666829. The reversal of 666828 is 828666.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 18523 = 666828 / (6 + 6 + 6 + 8 + 2 + 8).

It is a junction number, because it is equal to n+sod(n) for n = 666792 and 666801.

It is not an unprimeable number, because it can be changed into a prime (666821) by changing a digit.

666828 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 5 ways as a sum of consecutive naturals, for example, 9226 + ... + 9297.

2⁶⁶⁶⁸²⁸ is an apocalyptic number.

It is an amenable number.

666828 is an abundant number, since it is smaller than the sum of its proper divisors (1018856).

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

666828 is a wasteful number, since it uses less digits than its factorization.

666828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18533 (or 18528 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The square root of 666828 is about 816.5953710376. The cubic root of 666828 is about 87.3650927877.

The spelling of 666828 in words is "six hundred sixty-six thousand, eight hundred twenty-eight".