138108121 has 8 divisors (see below), whose sum is σ = 143062920. Its totient is φ = 133166208.

The previous prime is 138108109. The next prime is 138108133. The reversal of 138108121 is 121801831.

It is an interprime number because it is at equal distance from previous prime (138108109) and next prime (138108133).

It can be written as a sum of positive squares in 4 ways, for example, as 89038096 + 49070025 = 9436^2 + 7005^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138108121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138108521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22075 + ... + 27631.

It is an arithmetic number, because the mean of its divisors is an integer number (17882865).

Almost surely, 2^138108121 is an apocalyptic number.

It is an amenable number.

138108121 is a deficient number, since it is larger than the sum of its proper divisors (4954799).

138108121 is an equidigital number, since it uses as much as digits as its factorization.

138108121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6443.

The product of its (nonzero) digits is 384, while the sum is 25.

The square root of 138108121 is about 11751.9411588044. The cubic root of 138108121 is about 516.8998492820.

Adding to 138108121 its reverse (121801831), we get a palindrome (259909952).

The spelling of 138108121 in words is "one hundred thirty-eight million, one hundred eight thousand, one hundred twenty-one".