660666 has 16 divisors (see below), whose sum is σ = 1332000. Its totient is φ = 218448.

The previous prime is 660661. The next prime is 660683. The reversal of 660666 is 666066.

660666 is a modest number, since divided by 666 gives 660 as remainder.

It is not an unprimeable number, because it can be changed into a prime (660661) by changing a digit.

660666 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 7 ways as a sum of consecutive naturals, for example, 525 + ... + 1263.

It is an arithmetic number, because the mean of its divisors is an integer number (83250).

2⁶⁶⁰⁶⁶⁶ is an apocalyptic number.

660666 is an abundant number, since it is smaller than the sum of its proper divisors (671334).

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

660666 is a wasteful number, since it uses less digits than its factorization.

660666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 893.

The product of its (nonzero) digits is 7776, while the sum is 30.

The square root of 660666 is about 812.8136317755. The cubic root of 660666 is about 87.0951528615.

It can be divided in two parts, 660 and 666, that added together give a triangular number (1326 = T₅₁).

The spelling of 660666 in words is "six hundred sixty thousand, six hundred sixty-six".