138173688 has 192 divisors, whose sum is σ = 425748960. Its totient is φ = 41803776.

The previous prime is 138173683. The next prime is 138173689. The reversal of 138173688 is 886371831.

138173688 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138173683) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1222720 + ... + 1222832.

Almost surely, 2^138173688 is an apocalyptic number.

138173688 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 138173688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (212874480).

138173688 is an abundant number, since it is smaller than the sum of its proper divisors (287575272).

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

138173688 is a wasteful number, since it uses less digits than its factorization.

138173688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188 (or 172 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The square root of 138173688 is about 11754.7304520350. The cubic root of 138173688 is about 516.9816359533.

The spelling of 138173688 in words is "one hundred thirty-eight million, one hundred seventy-three thousand, six hundred eighty-eight".