1686668918009 has 4 divisors (see below), whose sum is σ = 1687006729716. Its totient is φ = 1686331106304.

The previous prime is 1686668917993. The next prime is 1686668918173. The reversal of 1686668918009 is 9008198666861.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 558527538409 + 1128141379600 = 747347^2 + 1062140^2 .

It is a cyclic number.

It is not a de Polignac number, because 1686668918009 - 2⁴ = 1686668917993 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1686668918009.

It is not an unprimeable number, because it can be changed into a prime (1686668948009) 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, 168898364 + ... + 168908349.

It is an arithmetic number, because the mean of its divisors is an integer number (421751682429).

Almost surely, 2^{1686668918009} is an apocalyptic number.

It is an amenable number.

1686668918009 is a deficient number, since it is larger than the sum of its proper divisors (337811707).

1686668918009 is an equidigital number, since it uses as much as digits as its factorization.

1686668918009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 337811706.

The product of its (nonzero) digits is 53747712, while the sum is 68.

The spelling of 1686668918009 in words is "one trillion, six hundred eighty-six billion, six hundred sixty-eight million, nine hundred eighteen thousand, nine".