666806712 has 128 divisors (see below), whose sum is σ = 1979631360. Its totient is φ = 184504320.

The previous prime is 666806687. The next prime is 666806717. The reversal of 666806712 is 217608666.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666806717) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 331903 + ... + 333905.

It is an arithmetic number, because the mean of its divisors is an integer number (15465870).

Almost surely, 2^666806712 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666806712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (989815680).

666806712 is an abundant number, since it is smaller than the sum of its proper divisors (1312824648).

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

666806712 is a wasteful number, since it uses less digits than its factorization.

666806712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2133 (or 2129 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 42.

The square root of 666806712 is about 25822.6007985253. The cubic root of 666806712 is about 873.6416308872.

The spelling of 666806712 in words is "six hundred sixty-six million, eight hundred six thousand, seven hundred twelve".