1665666686 has 8 divisors (see below), whose sum is σ = 2498700000. Its totient is φ = 832766688.

The previous prime is 1665666677. The next prime is 1665666689. The reversal of 1665666686 is 6866665661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1665666689) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8315 + ... + 58313.

It is an arithmetic number, because the mean of its divisors is an integer number (312337500).

Almost surely, 2^1665666686 is an apocalyptic number.

1665666686 is a deficient number, since it is larger than the sum of its proper divisors (833033314).

1665666686 is a wasteful number, since it uses less digits than its factorization.

1665666686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66658.

The product of its digits is 11197440, while the sum is 56.

The square root of 1665666686 is about 40812.5799968588. The cubic root of 1665666686 is about 1185.3939324216.

The spelling of 1665666686 in words is "one billion, six hundred sixty-five million, six hundred sixty-six thousand, six hundred eighty-six".