138686320 has 80 divisors (see below), whose sum is σ = 354263040. Its totient is φ = 50257152.

The previous prime is 138686279. The next prime is 138686321. The reversal of 138686320 is 23686831.

It is a tau number, because it is divible by the number of its divisors (80).

It is a self number, because there is not a number n which added to its sum of digits gives 138686320.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138686321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32977 + ... + 36943.

It is an arithmetic number, because the mean of its divisors is an integer number (4428288).

Almost surely, 2^138686320 is an apocalyptic number.

138686320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138686320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (177131520).

138686320 is an abundant number, since it is smaller than the sum of its proper divisors (215576720).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

138686320 is a wasteful number, since it uses less digits than its factorization.

138686320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4022 (or 4016 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 37.

The square root of 138686320 is about 11776.5156137119. The cubic root of 138686320 is about 517.6201903693.

The spelling of 138686320 in words is "one hundred thirty-eight million, six hundred eighty-six thousand, three hundred twenty".