138668 has 6 divisors (see below), whose sum is σ = 242676. Its totient is φ = 69332.

The previous prime is 138661. The next prime is 138679. The reversal of 138668 is 866831.

138668 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (138661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 17330 + ... + 17337.

It is an arithmetic number, because the mean of its divisors is an integer number (40446).

2¹³⁸⁶⁶⁸ is an apocalyptic number.

It is an amenable number.

138668 is a deficient number, since it is larger than the sum of its proper divisors (104008).

138668 is a wasteful number, since it uses less digits than its factorization.

138668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34671 (or 34669 counting only the distinct ones).

The product of its digits is 6912, while the sum is 32.

The square root of 138668 is about 372.3815247834. The cubic root of 138668 is about 51.7597397399.

The spelling of 138668 in words is "one hundred thirty-eight thousand, six hundred sixty-eight".