1668666687 has 8 divisors (see below), whose sum is σ = 2225336880. Its totient is φ = 1112220480.

The previous prime is 1668666683. The next prime is 1668666689. The reversal of 1668666687 is 7866668661.

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

It is not a de Polignac number, because 1668666687 - 2² = 1668666683 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1668666687.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1668666683) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37764 + ... + 69017.

It is an arithmetic number, because the mean of its divisors is an integer number (278167110).

Almost surely, 2^1668666687 is an apocalyptic number.

1668666687 is a deficient number, since it is larger than the sum of its proper divisors (556670193).

1668666687 is a wasteful number, since it uses less digits than its factorization.

1668666687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111993.

The product of its digits is 20901888, while the sum is 60.

The square root of 1668666687 is about 40849.3168486329. The cubic root of 1668666687 is about 1186.1051691804.

The spelling of 1668666687 in words is "one billion, six hundred sixty-eight million, six hundred sixty-six thousand, six hundred eighty-seven".