138121061 has 4 divisors (see below), whose sum is σ = 148745772. Its totient is φ = 127496352.

The previous prime is 138121007. The next prime is 138121069. The reversal of 138121061 is 160121831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 160121831 = 181 ⋅884651.

It can be written as a sum of positive squares in 2 ways, for example, as 86136961 + 51984100 = 9281^2 + 7210^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138121061 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138121069) 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, 5312336 + ... + 5312361.

It is an arithmetic number, because the mean of its divisors is an integer number (37186443).

Almost surely, 2^138121061 is an apocalyptic number.

It is an amenable number.

138121061 is a deficient number, since it is larger than the sum of its proper divisors (10624711).

138121061 is a wasteful number, since it uses less digits than its factorization.

138121061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10624710.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 138121061 is about 11752.4916932538. The cubic root of 138121061 is about 516.9159923712.

Adding to 138121061 its reverse (160121831), we get a palindrome (298242892).

The spelling of 138121061 in words is "one hundred thirty-eight million, one hundred twenty-one thousand, sixty-one".