138135881 has 8 divisors (see below), whose sum is σ = 148877064. Its totient is φ = 127411200.

The previous prime is 138135869. The next prime is 138135883. The reversal of 138135881 is 188531831.

It can be written as a sum of positive squares in 4 ways, for example, as 7376656 + 130759225 = 2716^2 + 11435^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 138135881 - 2²⁶ = 71027017 is a prime.

It is a super-2 number, since 2×138135881² = 38163043239292322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138135883) 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, 17495 + ... + 24131.

It is an arithmetic number, because the mean of its divisors is an integer number (18609633).

Almost surely, 2^138135881 is an apocalyptic number.

It is an amenable number.

138135881 is a deficient number, since it is larger than the sum of its proper divisors (10741183).

138135881 is a wasteful number, since it uses less digits than its factorization.

138135881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8251.

The product of its digits is 23040, while the sum is 38.

The square root of 138135881 is about 11753.1221809356. The cubic root of 138135881 is about 516.9344795857.

The spelling of 138135881 in words is "one hundred thirty-eight million, one hundred thirty-five thousand, eight hundred eighty-one".