138320208 has 120 divisors (see below), whose sum is σ = 428363208. Its totient is φ = 41389056.

The previous prime is 138320197. The next prime is 138320213. The reversal of 138320208 is 802023831.

138320208 is a `hidden beast` number, since 138 + 320 + 208 = 666.

138320208 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 1710864 + 136609344 = 1308^2 + 11688^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 68266 + ... + 70262.

Almost surely, 2^138320208 is an apocalyptic number.

138320208 is a gapful number since it is divisible by the number (18) 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 138320208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (214181604).

138320208 is an abundant number, since it is smaller than the sum of its proper divisors (290043000).

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

138320208 is a wasteful number, since it uses less digits than its factorization.

138320208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2061 (or 2052 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 138320208 is about 11760.9611852093. The cubic root of 138320208 is about 517.1643079501.

The spelling of 138320208 in words is "one hundred thirty-eight million, three hundred twenty thousand, two hundred eight".