666766 has 4 divisors (see below), whose sum is σ = 1000152. Its totient is φ = 333382.

The previous prime is 666751. The next prime is 666769. The reversal of 666766 is 667666.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666769) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166690 + ... + 166693.

It is an arithmetic number, because the mean of its divisors is an integer number (250038).

2⁶⁶⁶⁷⁶⁶ is an apocalyptic number.

666766 is a deficient number, since it is larger than the sum of its proper divisors (333386).

666766 is a wasteful number, since it uses less digits than its factorization.

666766 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333385.

The product of its digits is 54432, while the sum is 37.

The square root of 666766 is about 816.5574076573. The cubic root of 666766 is about 87.3623850411.

Subtracting 666766 from its reverse (667666), we obtain a square (900 = 30²).

The spelling of 666766 in words is "six hundred sixty-six thousand, seven hundred sixty-six".