138521686109 has 8 divisors (see below), whose sum is σ = 146717101440. Its totient is φ = 130331502016.

The previous prime is 138521686087. The next prime is 138521686133. The reversal of 138521686109 is 901686125831.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138521686109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138521686169) 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, 1253219 + ... + 1359264.

It is an arithmetic number, because the mean of its divisors is an integer number (18339637680).

Almost surely, 2^138521686109 is an apocalyptic number.

It is an amenable number.

138521686109 is a deficient number, since it is larger than the sum of its proper divisors (8195415331).

138521686109 is a wasteful number, since it uses less digits than its factorization.

138521686109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2615619.

The product of its (nonzero) digits is 622080, while the sum is 50.

It can be divided in two parts, 13852 and 1686109, that added together give a palindrome (1699961).

The spelling of 138521686109 in words is "one hundred thirty-eight billion, five hundred twenty-one million, six hundred eighty-six thousand, one hundred nine".