138538836 has 60 divisors (see below), whose sum is σ = 371036820. Its totient is φ = 45048960.

The previous prime is 138538801. The next prime is 138538853. The reversal of 138538836 is 638835831.

138538836 is a `hidden beast` number, since 1 + 38 + 538 + 83 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 77792400 + 60746436 = 8820^2 + 7794^2 .

It is a junction number, because it is equal to n+sod(n) for n = 138538791 and 138538800.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 8070 + ... + 18498.

It is an arithmetic number, because the mean of its divisors is an integer number (6183947).

Almost surely, 2^138538836 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138538836, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (185518410).

138538836 is an abundant number, since it is smaller than the sum of its proper divisors (232497984).

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

138538836 is a wasteful number, since it uses less digits than its factorization.

138538836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10486 (or 10475 counting only the distinct ones).

The product of its digits is 414720, while the sum is 45.

The square root of 138538836 is about 11770.2521638238. The cubic root of 138538836 is about 517.4366400059.

The spelling of 138538836 in words is "one hundred thirty-eight million, five hundred thirty-eight thousand, eight hundred thirty-six".