138028121 has 16 divisors (see below), whose sum is σ = 172677120. Its totient is φ = 107185680.

The previous prime is 138028109. The next prime is 138028127. The reversal of 138028121 is 121820831.

It is not a de Polignac number, because 138028121 - 2⁶ = 138028057 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (138028127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20720 + ... + 26558.

It is an arithmetic number, because the mean of its divisors is an integer number (10792320).

Almost surely, 2^138028121 is an apocalyptic number.

138028121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

138028121 is a deficient number, since it is larger than the sum of its proper divisors (34648999).

138028121 is a wasteful number, since it uses less digits than its factorization.

138028121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6164.

The product of its (nonzero) digits is 768, while the sum is 26.

The square root of 138028121 is about 11748.5369727469. The cubic root of 138028121 is about 516.8000241723.

Adding to 138028121 its reverse (121820831), we get a palindrome (259848952).

The spelling of 138028121 in words is "one hundred thirty-eight million, twenty-eight thousand, one hundred twenty-one".