1668138318605 has 16 divisors (see below), whose sum is σ = 2184027366528. Its totient is φ = 1213034472000.

The previous prime is 1668138318559. The next prime is 1668138318619. The reversal of 1668138318605 is 5068138318661.

It is not a de Polignac number, because 1668138318605 - 2¹² = 1668138314509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1533281 + ... + 2384790.

It is an arithmetic number, because the mean of its divisors is an integer number (136501710408).

Almost surely, 2^{1668138318605} is an apocalyptic number.

It is an amenable number.

1668138318605 is a deficient number, since it is larger than the sum of its proper divisors (515889047923).

1668138318605 is a wasteful number, since it uses less digits than its factorization.

1668138318605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3925828.

The product of its (nonzero) digits is 4976640, while the sum is 56.

Adding to 1668138318605 its sum of digits (56), we get a palindrome (1668138318661).

The spelling of 1668138318605 in words is "one trillion, six hundred sixty-eight billion, one hundred thirty-eight million, three hundred eighteen thousand, six hundred five".