138660678 has 48 divisors (see below), whose sum is σ = 326800656. Its totient is φ = 42235200.

The previous prime is 138660649. The next prime is 138660751. The reversal of 138660678 is 876066831.

138660678 is a `hidden beast` number, since 1 + 38 + 6 + 606 + 7 + 8 = 666.

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, 20701 + ... + 26567.

It is an arithmetic number, because the mean of its divisors is an integer number (6808347).

Almost surely, 2^138660678 is an apocalyptic number.

138660678 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 138660678, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (163400328).

138660678 is an abundant number, since it is smaller than the sum of its proper divisors (188139978).

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

138660678 is a wasteful number, since it uses less digits than its factorization.

138660678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5989 (or 5986 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The square root of 138660678 is about 11775.4268712434. The cubic root of 138660678 is about 517.5882871145.

The spelling of 138660678 in words is "one hundred thirty-eight million, six hundred sixty thousand, six hundred seventy-eight".