138533881 has 2 divisors, whose sum is σ = 138533882. Its totient is φ = 138533880.

The previous prime is 138533869. The next prime is 138533909. The reversal of 138533881 is 188335831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 123010281 + 15523600 = 11091^2 + 3940^2 .

It is a cyclic number.

It is not a de Polignac number, because 138533881 - 2⁵ = 138533849 is a prime.

It is a super-2 number, since 2×138533881² = 38383272369844322, which contains 22 as substring.

It is equal to p_7833883 and since 138533881 and 7833883 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (138533821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69266940 + 69266941.

It is an arithmetic number, because the mean of its divisors is an integer number (69266941).

Almost surely, 2^138533881 is an apocalyptic number.

It is an amenable number.

138533881 is a deficient number, since it is larger than the sum of its proper divisors (1).

138533881 is an equidigital number, since it uses as much as digits as its factorization.

138533881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69120, while the sum is 40.

The square root of 138533881 is about 11770.0416736730. The cubic root of 138533881 is about 517.4304710279.

The spelling of 138533881 in words is "one hundred thirty-eight million, five hundred thirty-three thousand, eight hundred eighty-one".