138978719 has 8 divisors (see below), whose sum is σ = 158205312. Its totient is φ = 120850840.

The previous prime is 138978713. The next prime is 138978731. The reversal of 138978719 is 917879831.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 138978719 - 2²⁴ = 122201503 is a prime.

It is a super-2 number, since 2×138978719² = 38630168669761922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138978713) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 274409 + ... + 274914.

It is an arithmetic number, because the mean of its divisors is an integer number (19775664).

Almost surely, 2^138978719 is an apocalyptic number.

138978719 is a deficient number, since it is larger than the sum of its proper divisors (19226593).

138978719 is a wasteful number, since it uses less digits than its factorization.

138978719 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 549357.

The product of its digits is 762048, while the sum is 53.

The square root of 138978719 is about 11788.9235725744. The cubic root of 138978719 is about 517.9837094801.

It can be divided in two parts, 1389 and 78719, that added together give a palindrome (80108).

The spelling of 138978719 in words is "one hundred thirty-eight million, nine hundred seventy-eight thousand, seven hundred nineteen".