138865 has 4 divisors (see below), whose sum is σ = 166644.
Its totient is φ = 111088.
The previous prime is 138863. The next prime is 138869. The reversal of 138865 is 568831.
138865 = 2632 + 2642.
138865 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
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 69169 + 69696 = 263^2 + 264^2
It is a cyclic number.
It is not a de Polignac number, because 138865 - 21 = 138863 is a prime.
It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.
It is a d-powerful number, because it can be written as 1 + 39 + 83 + 85 + 65 + 57 .
It is a Duffinian number.
It is a plaindrome in base 7.
It is a zygodrome in base 7.
It is not an unprimeable number, because it can be changed into a prime (138863) 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, 13882 + ... + 13891.
It is an arithmetic number, because the mean of its divisors is an integer number (41661).
2138865 is an apocalyptic number.
138865 is the 264-th centered square number.
It is an amenable number.
138865 is a deficient number, since it is larger than the sum of its proper divisors (27779).
138865 is an equidigital number, since it uses as much as digits as its factorization.
138865 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 27778.
The product of its digits is 5760, while the sum is 31.
The square root of 138865 is about 372.6459445640.
The cubic root of 138865 is about 51.7842391290.
The spelling of 138865 in words is "one hundred thirty-eight thousand, eight hundred sixty-five".