138723878 has 32 divisors (see below), whose sum is σ = 223257600. Its totient is φ = 64520064.

The previous prime is 138723877. The next prime is 138723881. The reversal of 138723878 is 878327831.

It is a happy number.

It is a Smith number, since the sum of its digits (47) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138723877) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 272288 + ... + 272796.

It is an arithmetic number, because the mean of its divisors is an integer number (6976800).

Almost surely, 2^138723878 is an apocalyptic number.

138723878 is a deficient number, since it is larger than the sum of its proper divisors (84533722).

138723878 is a wasteful number, since it uses less digits than its factorization.

138723878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 704.

The product of its digits is 451584, while the sum is 47.

The square root of 138723878 is about 11778.1101200490. The cubic root of 138723878 is about 517.6669121715. Note that the first 3 decimals are identical.

The spelling of 138723878 in words is "one hundred thirty-eight million, seven hundred twenty-three thousand, eight hundred seventy-eight".