138831666643685 has 4 divisors (see below), whose sum is σ = 166597999972428. Its totient is φ = 111065333314944.

The previous prime is 138831666643673. The next prime is 138831666643711. The reversal of 138831666643685 is 586346666138831.

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 31124091736609 + 107707574907076 = 5578897^2 + 10378226^2 .

It is a cyclic number.

It is not a de Polignac number, because 138831666643685 - 2⁸ = 138831666643429 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13883166664364 + ... + 13883166664373.

It is an arithmetic number, because the mean of its divisors is an integer number (41649499993107).

Almost surely, 2^{138831666643685} is an apocalyptic number.

It is an amenable number.

138831666643685 is a deficient number, since it is larger than the sum of its proper divisors (27766333328743).

138831666643685 is an equidigital number, since it uses as much as digits as its factorization.

138831666643685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27766333328742.

The product of its digits is 2149908480, while the sum is 74.

The spelling of 138831666643685 in words is "one hundred thirty-eight trillion, eight hundred thirty-one billion, six hundred sixty-six million, six hundred forty-three thousand, six hundred eighty-five".