1666187666 has 48 divisors (see below), whose sum is σ = 3087225792. Its totient is φ = 668675040.

The previous prime is 1666187641. The next prime is 1666187701. The reversal of 1666187666 is 6667816661.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 60845 + ... + 83871.

It is an arithmetic number, because the mean of its divisors is an integer number (64317204).

Almost surely, 2^1666187666 is an apocalyptic number.

1666187666 is a deficient number, since it is larger than the sum of its proper divisors (1421038126).

1666187666 is a wasteful number, since it uses less digits than its factorization.

1666187666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23087 (or 23076 counting only the distinct ones).

The product of its digits is 2612736, while the sum is 53.

The square root of 1666187666 is about 40818.9620887156. The cubic root of 1666187666 is about 1185.5175069960.

The spelling of 1666187666 in words is "one billion, six hundred sixty-six million, one hundred eighty-seven thousand, six hundred sixty-six".