666788 has 12 divisors (see below), whose sum is σ = 1180620. Its totient is φ = 329472.

The previous prime is 666773. The next prime is 666811. The reversal of 666788 is 887666.

It can be written as a sum of positive squares in 2 ways, for example, as 61504 + 605284 = 248^2 + 778^2 .

It is a plaindrome in base 10.

It is a congruent number.

It is an unprimeable number.

666788 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, 581 + ... + 1292.

It is an arithmetic number, because the mean of its divisors is an integer number (98385).

2⁶⁶⁶⁷⁸⁸ is an apocalyptic number.

It is an amenable number.

666788 is a deficient number, since it is larger than the sum of its proper divisors (513832).

666788 is a wasteful number, since it uses less digits than its factorization.

666788 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1966 (or 1964 counting only the distinct ones).

The product of its digits is 96768, while the sum is 41.

The square root of 666788 is about 816.5708787362. The cubic root of 666788 is about 87.3633458736.

The spelling of 666788 in words is "six hundred sixty-six thousand, seven hundred eighty-eight".