1665766666 has 16 divisors (see below), whose sum is σ = 2531923200. Its totient is φ = 821806128.

The previous prime is 1665766649. The next prime is 1665766673. The reversal of 1665766666 is 6666675661.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 366355 + ... + 370873.

It is an arithmetic number, because the mean of its divisors is an integer number (158245200).

Almost surely, 2^1665766666 is an apocalyptic number.

1665766666 is a deficient number, since it is larger than the sum of its proper divisors (866156534).

1665766666 is a wasteful number, since it uses less digits than its factorization.

1665766666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6933.

The product of its digits is 9797760, while the sum is 55.

The square root of 1665766666 is about 40813.8048459097. The cubic root of 1665766666 is about 1185.4176493143.

The spelling of 1665766666 in words is "one billion, six hundred sixty-five million, seven hundred sixty-six thousand, six hundred sixty-six".