666428 has 12 divisors (see below), whose sum is σ = 1332912. Its totient is φ = 285600.

The previous prime is 666427. The next prime is 666431. The reversal of 666428 is 824666.

It is a happy number.

666428 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

666428 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 666394 and 666403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666427) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11873 + ... + 11928.

It is an arithmetic number, because the mean of its divisors is an integer number (111076).

2⁶⁶⁶⁴²⁸ is an apocalyptic number.

It is an amenable number.

666428 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

666428 is a wasteful number, since it uses less digits than its factorization.

666428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23812 (or 23810 counting only the distinct ones).

The product of its digits is 13824, while the sum is 32.

The square root of 666428 is about 816.3504149567. The cubic root of 666428 is about 87.3476205025.

The spelling of 666428 in words is "six hundred sixty-six thousand, four hundred twenty-eight".