1666566666 has 12 divisors (see below), whose sum is σ = 3610894482. Its totient is φ = 555522216.

The previous prime is 1666566653. The next prime is 1666566701. The reversal of 1666566666 is 6666656661.

It can be written as a sum of positive squares in only one way, i.e., 1131986025 + 534580641 = 33645^2 + 23121^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 46293501 + ... + 46293536.

Almost surely, 2^1666566666 is an apocalyptic number.

1666566666 is an abundant number, since it is smaller than the sum of its proper divisors (1944327816).

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

1666566666 is a wasteful number, since it uses less digits than its factorization.

1666566666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92587045 (or 92587042 counting only the distinct ones).

The product of its digits is 8398080, while the sum is 54.

The square root of 1666566666 is about 40823.6042749780. The cubic root of 1666566666 is about 1185.6073882423.

The spelling of 1666566666 in words is "one billion, six hundred sixty-six million, five hundred sixty-six thousand, six hundred sixty-six".