138400138 has 8 divisors (see below), whose sum is σ = 208196100. Its totient is φ = 69001440.

The previous prime is 138400127. The next prime is 138400139. The reversal of 138400138 is 831004831.

138400138 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 109056249 + 29343889 = 10443^2 + 5417^2 .

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

It is not an unprimeable number, because it can be changed into a prime (138400139) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 98443 + ... + 99838.

Almost surely, 2^138400138 is an apocalyptic number.

138400138 is a deficient number, since it is larger than the sum of its proper divisors (69795962).

138400138 is a wasteful number, since it uses less digits than its factorization.

138400138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198632.

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 138400138 is about 11764.3588010567. The cubic root of 138400138 is about 517.2639053118.

Adding to 138400138 its reverse (831004831), we get a palindrome (969404969).

The spelling of 138400138 in words is "one hundred thirty-eight million, four hundred thousand, one hundred thirty-eight".