138881 has 4 divisors (see below), whose sum is σ = 143700. Its totient is φ = 134064.

The previous prime is 138869. The next prime is 138883. The reversal of 138881 is 188831.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 36481 + 102400 = 191^2 + 320^2 .

It is a cyclic number.

It is not a de Polignac number, because 138881 - 2¹⁴ = 122497 is a prime.

It is a super-2 number, since 2×138881² = 38575864322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (29), and also a Moran number because the ratio is a prime number: 4789 = 138881 / (1 + 3 + 8 + 8 + 8 + 1).

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 138881.

It is not an unprimeable number, because it can be changed into a prime (138883) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2366 + ... + 2423.

It is an arithmetic number, because the mean of its divisors is an integer number (35925).

2¹³⁸⁸⁸¹ is an apocalyptic number.

It is an amenable number.

138881 is a deficient number, since it is larger than the sum of its proper divisors (4819).

138881 is an equidigital number, since it uses as much as digits as its factorization.

138881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4818.

The product of its digits is 1536, while the sum is 29.

The square root of 138881 is about 372.6674120446. The cubic root of 138881 is about 51.7862279095.

The spelling of 138881 in words is "one hundred thirty-eight thousand, eight hundred eighty-one".