138181836 has 72 divisors (see below), whose sum is σ = 355175184. Its totient is φ = 41783040.

The previous prime is 138181829. The next prime is 138181853. The reversal of 138181836 is 638181831.

138181836 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a junction number, because it is equal to n+sod(n) for n = 138181794 and 138181803.

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, 123150 + ... + 124266.

Almost surely, 2^138181836 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 138181836, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (177587592).

138181836 is an abundant number, since it is smaller than the sum of its proper divisors (216993348).

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

138181836 is a wasteful number, since it uses less digits than its factorization.

138181836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1211 (or 1196 counting only the distinct ones).

The product of its digits is 27648, while the sum is 39.

The square root of 138181836 is about 11755.0770307982. The cubic root of 138181836 is about 516.9917977615.

The spelling of 138181836 in words is "one hundred thirty-eight million, one hundred eighty-one thousand, eight hundred thirty-six".